Internet magically gets faster when opening speedtest?

Yes, this is true. This is why Netflix runs fast.com: it serves Netflix content from Netflix servers, so if ISPs want to prioritize fast.com content they'll have to prioritize Netflix content as well. Of course, that doesn't help non-Netflix sites...

I was on the phone with a buddy trying to troubleshoot Local file transfer speeds vs Speedtest results.

Speedtest kept reporting 100Mb/s range speeds (the tier he was paying for). Local file transfers however were stuck in the 1MB/s range.

After some questions and troubleshooting he discovered that he had used a 10Mb/s hub instead of a 1Gb/s switch that was sitting right next to it. A simple mixup.

His internet connection was also plugged into that same 10Mb/s hub.

There is NO WAY his PC could have reported 100Mb/s to speedtest.

Do not trust them for accurate results.

Unlikely your suspicions are correct. Provisioning high QoS to the speedtest site is common practice (see fast.com for countermeasures), but changing the entire subscriber QoS because traffic to one particular destination is detected seems like too much work and doesn't really achieve anything useful.

If you are on a wireless network (either your upstream from a WISP, or internally on your own network), then I'd suspect some wireless air access control syndrome is the cause -- e.g. stations are usually randomly fighting for air, but when you pull down your big speed test file that ends up putting the network in a state where your station gets all the air time. Lo and behold all your traffic has better QoS. Basically your speedtest traffic, because it is a constant stream, shoved everyone else off the air and allowed your other traffic to get through at the same time as a result.

Lots of people here have already mentioned the Netflix fast.com test, which is indeed good.

But also worthy of recommendation IHMO is the Cloudflare one (speed.cloudflare.com). Main reason I say that is its one of the few that measures jitter (or at least openly exposes the measurement).

I don't know if it's related but some time ago when I was testing the Arch distro, Garuda, I noticed that my Internet was very slow (Kbps) when updating. To test my speed I loaded fast.com and something strange happened, while the test lasted, the update speed was normal (at the top of my Internet plan). Once it finished loading it was slow again. At first glance it seemed that my ISP (Tigo) gave priority to Netflix and released the 'normal' speed when loading the test (fast.com is Netflix's). I made a script that called fast.com every time I updated my OS and it worked super well. I even used the script for other downloads. After switching to Arcolinux I stopped noticing that network behavior and stopped using the script.

> Is there a way I can test this more scientifically?

How about the following?:

1. Choose a dozen or so public files on hosts known to have high bandwidth (Google or Microsoft perhaps). Maybe choose a couple of public legal torrents too.

2. Write a script to download all the chosen files (either sequentially or concurrently), and emit timing information.

3. Run that script a couple of times a day at random times. Try to cover weekdays and weekends, days and nights.

4. Repeat 3 but running a speed test first each time. See if there is any statistically significant difference.

Yes, and, the joke in the industry is that network speed tests are to network performance what the Volkswagen Diesel was to emission tests :).

All carriers implement various types of throttling or rate limiting, for a lot of reasons (anti-ddos, cost control, etc.)

But; universally, they bypass these rate controls such as Cisco PGW ADC (Application Detection and Control) and LTE eNB ABR for wireless as examples, and many others similar features that limit the rate the user actually gets. And in almost all cases, these systems are designed to allow speed tests to bypass the rate limiting.

Commercial Speed tests are in no way a valid or reliable way of understanding the quality of a network service. I am a little surprised that this is breaking news on HN however. I would think this would be pretty well understood by this community?

BTW. Fast.com does is not always immune to this "Volkswagen diesel" effect. The only way to know for sure is to have a VM or bare metal server someplace and do an iperf to it.

I was cursing on my ISP for a long time till I understood that Im on a 100Mbit wifi.

Then added a wire connection to my server and instantly 10x the speed :^]

Dont be like me, have wires set up everywhere where needed.

Not very scientific but you can try something that is unlikely to be whitelisted.

Eg. http://134.209.196.181:8080 This is an instance of https://github.com/e7d/speedtest running on Digital Ocean in Amsterdam.

Ah yes, the internet's worst kept secret. The reasons behind it however are less obvious.

Yes, to a certain extent your ISP is watching to see if you run a speedtest and will open up more bandwidth to you in the event you do. However, if they were throttling you, which is not guaranteed, the most likely reason for throttling you is that the network hub for your neighborhood was under an heavy load, and they throttled everyone on your backbone hub to ensure that critical operations don't experience interruptions.

What you might consider critical operations might not agree with what your ISP considers critical of course, but they're a for profit business rather than a utility. So, what you consider a valid reason for throttling you doesn't count for squat. The reason they sped you up is that despite the fact that they carefully crafted their service contract to say they legally can throttle you for any reason or no reason at all, it reduces the number of complaints calls they don't intend to do anything about.

It also gives them plausible deniablity, and weirdly enough a useful metric for identifying hardware problems. They can simply make you think that the problem was the individual web service you were connecting to, or maybe just all of cloud flare. But more than that, they are able to track the number of times in a day that people visited a speedtest site, and whether they were able to get your speed up to the expected level. This functions as an early warning sign that they need to increase the total available bandwidth in an area if those numbers become what your ISP considers unacceptable.

Again, what your ISP considers unacceptable and what you consider unacceptable are not the same, but they're a for profit business rather than a regulated non-profit utility.

This is real. I have had it confirmed to me by a Comcast employee. And really, this shouldn't surprise anyone.

this is true, in my country, it's a well known thing that the internet gets un-throttled when accessing speedtest, and someone ingenious made a script to keep running speedtest-cli in background to keep the internet working at full speed

https://github.com/orz811017/boost_bandwidth_via_speedtest

Yes, that is common. Back when I used to work for an ISP, all of our main competitors have whitelisted speedtest servers to sidestep their shaping and sometimes even ran their own, just to look good on the results page. The fact that other webs instantly load might be just an implementation quirk; the QoS might get reset for a second when loading the speedtest page.

You can see what ISP traffic shaping actually does when you have a server on reliable backbone link outside of given ISP network by trying to download or upload large file to it and measuring. Bandwidth changes usually aren't too smooth and often you can see "stairs" on measurement graph as the speed drops the more data you transmit.

This shows how the whole "speed UP TO xyz mbits" marketing trick really works.

Try one they probably don't have on their whitelist, like https://proof.ovh.net/

I had the same thing with my previous internet provider, I even set up iperf3 test to confirm that and it was clear when watching anything from youtube. It was so bad that it could barely keep up with 144p on YouTube and when speed test was running i could easily watch anything in 4k, but imidietely when test was finished everything was back to snail speed. I ended up with doing download only speed test in loop from cli version, and even with this extra traffic everything was much faster and with better latencies...

Impossible to know for sure, but the ROI on “accelerate packets that match an IP whitelist that is drawn nightly from the DNS records for well-traveled speed test sites” must be quite high.

This is one feature I like from my Wifi router. It does regular speed tests and tracks the results over time. I like to think it reminds my ISP that I want the speed I'm paying for.

It wouldn't surprise me one bit if the ISP was doing something like this. It's an easy way to make their service look better and there are few consequences for getting caught. It's also hard to prove conclusively that it's happening.

Another weird one: Open fast.com and check your speed.

Now reload the page and and run it again but as soon as it starts, open another tab and do some browsing.

The second test gives me higher speeds consistently.

I was having issues with slow load times, high latency, dropped packets, the works. I had been profiling it and logging my bandwidth with (iirc) iperf on a raspi, over the past 48h. When I felt like I had collected enough data, I called Spectrum to give em a piece of my mind. One of the first things they had me do was use their online speedtest. Came up with 100Mbps...I had been getting 10 on iperf.

Suddenly, my traffic quality was mysteriously better.

No idea what was actually going on, but the whole thing was a bit sus.

I definitely recommend using your own server and profiling tools if you are suspicious of speedtest.

Speed tests often test last mile. That’s only part of real world performance. Some examples of other factors to real world stuff:

1. If you internet provider has limited bandwidth when it connects to other parts of the internet. I used to have a problem where my ISP has one connection out of its network. That bandwidth was limited and caused real world issues.

2. TCP can and often does involve multiple round trips. As web pages have grown in size it’s had an impact on performance at the network level

Increased bandwidth in the last mile doesn’t solve for these types of issues

Well, I've had this experience as well, where I note the performance is so bad that I go to the speed test page of my internet provider and then it ends up being ok. However I have a pretty solid suspicion that they have not done anything to monitor usage and stop throttling when seeing a check because:

1. I used to consult (for two years) in the department of my internet provider that would have had to do the reporting to the people who would have controlled throttling and even worked on the speed test page at times and there was no project to do that.

2. There was evidently no known and talked about throttling project among the hundreds of techies working at the business.

3. This place would not have been able to pull off the coordination between departments required to do this and also keep it a secret, and I'm betting most Internet providers would be even more incapable of doing something so nefarious.

4. The department providing customer support would have had to be in league with whatever department providing throttling, however KPIs for the customer support would of course have been negatively impacted by the many people calling in to report negative bandwidth usage. Thus they would have had to be in league with another division of the company to make sure they underperformed and thus did not get good bonuses etc. That would be an enviable level of dedication I must say.

Study the traffic in Wireshark, and also sniff upstream of your router to compare. I'd bet it's your router before I'd bet it's your isp.

I gave up with cots routers a while back, and life has been significantly improved. I wrote it up here https://res.rag.pub/2020-11-1-an-home-router.html

It would be very expensive for ISPs to implement this kind of thing.

So Occam’s Razor makes me doubt it. ISPs do all kinds of tricks to make speed tests work well, co-locating, prioritising that path etc. But I don’t think they’ve complex profiling equipment that slows everything, then removes the slowdown when they see DNS/SNI for speedtest, then apply it again after.

Also been working for ISPs for 20+ years and never heard of it. Only exception may be in cellular with their fancy PCRF boxes, but even there I think it’s much more common to throttle one class, and not another, than to slow everything but switch the throttle on/off if you access a particular site.

If this is true you could easily game it by running speed test all the time. All you gotta do is throttle bandwidth to the speed test servers yourself somehow (so the speed test goes slow and doesn’t eat your available bandwidth.) Then you’ll be permanently in the “they’re doing speedtest give them full speed” category.

As other commentets have pointed out: you are not insane :)

Another speedtester you can try: https://www.dslreports.com/speedtest

Top Chinese university here. In China we had to use proxies to access certain foreign sites, such as Google and Hacker News, because of censorship. Proxies were slow but speedtest was fast, so one of the guys tried including "speedtest" as a fake hostname for the proxies. Speed was immediately up to 1Gbps rather than 10Mbps.

I notice this too! I really hope I'm insane, because the implications of this are... concerning

I was having a similar problem at home, but it wasn't remedied by anything like that. Then, one day I've installed DNSMasq on a small SBC on my local network, then everything became blazing fast.

That day I've found out that my ADSL modem is not very good at making huge amount of DNS queries to outside world, and with a fast DNS resolver, Firefox is actually as fast as Chrome.

So, make sure that you can access your DNS servers with the speed they need to be accessed for a good network experience.

If you want to test whether this is true, make your own speedtest. Download the same Linux ISO from different mirrors, or try different speedtest mirrors to go further than your ISP.

My ISP's support told me to always use their local copy (https://speed.aussiebroadband.com.au/) as it avoids routing issues downstream but more importantly, it logs the history onto my account for them to view.

The numbers are often higher than what I pay for, but I think they are honest. When I was having connection issues (dialup-tier download speeds, 20 megabit upload) it was reflected accurately. Since I trust them, I like this arrangement. If I didn't then I wouldn't.

I suspect it is a bias effect. Sometimes, connections are slow for a few minutes: temporary network congestion, maintenance, interference, etc... That's the time you start to check, and by coincidence, things get better as you are checking. I don't think that your test triggered anything.

What is true however is that speed test servers are often located right next to you and maybe given priority access. It means that you can get great numbers despite a poor global connection, but it shouldn't make anything else go better.

So the trick is to always be running a speed-test in the background?

Some people in the UK may remember this problem at the end of March? https://www.lbc.co.uk/news/british-gas-eon-websites-crash-me...

So someone I know couldnt submit their meter reading at various times throughout the 31st of March so I did it for them simply by doing a tracert to the server handling the meter readings in question for Eon.

In the time it took for the tracert to complete I was able to log in as them and submit their meter reading!

Before the tracert trick, I too was having lots of problems logging in as them trying to submit their meter reading.

I did the tracert because I was going to VPN to physically get closer to their server, possible even within the same data centre and as it happens it was located on a globally recognised brands scalable cloud server so there was no reason really for these server to not handle all these meter readings!

The cynic in me thinks this was an attempt by some energy firms to consolidate their market positions by messing customers around with higher energy bills which reinforces the adage nice guys finish last, or when looking back over several months, the nice companies go bust!

So some IT staff working for Eon will be getting their comeuppance, because they didnt let their servers scale up to meet demand and the so called free british press are extremely quiet on this point, because they dont want to reduce advertising income!

There are so many legal ways to be criminal!

ISPs screwing with speedtest results is quite common and plausible.

The claim that it affects other tabs...seems wildly unlikely to me though. QoS and shaping is per service and per target.

All providers managing their speedtest servers with QoS. These servers will be handled as a business critical system. All other services are available as they are, if not specified in a contract. So, you might toss your tinfoil hat into trashcan. Yet better you can use mtr (https://www.bitwizard.nl/mtr/) to just find the real source of the problem.

Just run a Cron job to ping speedtest.net every 1 minute.

My ISP does the prioritization whenever you do a DNS lookup for speedtest.net. You don't actually need to run the test.

Try with LibreSpeed?

Hosted version: https://librespeed.org/

Self hosted version: https://github.com/librespeed/speedtest

For those who need to document lower speeds than SLAs from their ISPs, this will help you check for chicanery, shenanigans, and sneaky QoS. Recommend.

I don't trust speedtests. There are all kinds of wrong incentives, similar to GPU benchmarks. One thing I noticed was that the data speedtest.net sends has really low entropy. It just repeats 10 bytes. If I ran an ISP I would...

So I wrote chargen2p [1] as an extension to the classical chargen protocol.

I use it together with a Prometheus exporter [2] I wrote to periodically check my laptop's connectivity. The actual check runs over Wireguard, since I didn't want to open my chargen2p server to the public. This only checks download speeds, mind you. (The chargen2p library exports upload metrics, but the exporter doesn't use it.)

My graphs tell me the average is ~5 MBps, so 40 Mbps. This is between me (Switzerland) and a Hetzner DC in Germany. speedtest.net just now claimed 160 Mbps.

[1] https://github.com/tommie/chargen2p

[2] https://github.com/tommie/prometheus-connectivity-exporter

Alongside probably whitelisting : Most speed test sites hit the ISP cache or peered traffic and hence are much faster.

you can inspect fast.com and see this in action: It will show up something like "ipv4-c209-sea001-ix.1.oca.nflxvideo.net" Which is their openconnect [1] location in Seattle IX.

In many cases you will probably see a prefix indicating your ISP - Most ISPs with some scale host their own caches or peer with an internet exchange directly.

Incase of speedtest - its the same story most ISPs host servers locally and speedtest's website generally tests from it

Most of my ISP screw ups are involve content which isnt cached and its difficult to convey that when your netflix is able to stream 4K content easily but struggling to download a 100mb file of some AWS region :/

I sometimes use proof.ovh.net and ping.online.net to test using iperf also ec2-reachability.amazonaws.com helps debug if ISP is having issues with connecting to AWS (more open than not thats the case with mine)

--- [1] https://openconnect.netflix.com

This has been happening to me for a long time. I have an alias set up in my terminal that will send a ping to speedtest.net every few seconds to make my ISP think that I am doing a speedtest. I will start it if I am noticing throttling. It seems to work some of the time, but not if the network is extremely overloaded.

Something like this: alias pingspeed="ping -i 4 speedtest.net"

Downloading a large file from Microsoft is a good test (their end wont be the bottleneck, and they have a lot of large files you can download)

I wonder if one could route all traffic through a speedtest site

No need for tinfoil hats. This is a very basic networking consideration: peering. I've worked at ISPs and we would see traffic struggle through some of our contracted peers but not others all the time. It would take a while for all routes to update, and that if we had rerouting setup properly (not always the case). It gets extra complicated when you add BGP to the mix.

Long story short, most ISPs run or are well peered to data centers nearby, which is where speed tests are normally hosted at. For traffic outside of those hops, peering issues can lead to a multitude of issues... and you don't have to be evil for that to happen. No ISPs control the entire IP path between the client and server (with extremely narrow coincidental exceptions).

i am using spectrum business and i’ve been paying close to $200/m. this is in LA in a residential building. the speed looks good when i run a test but i notice that page loading times are total shit at least initially. if i start a download for a video game that ramps up quickly in speed but i actually don’t need that. what i really want is very fast resolving and page loading, which is different than just large downloads. i am wondering if other people here have the same problem and what they have done to fix this. i have been thinking about trying to replace my spectrum router with a pfsense box while still using their modem. but not sure if that will fix the issue. i use debian workstations and have gigabit ethernet for my internal network.

Good way to run a business. Run your business and on the side create a speed test on the side and call it the only accurate speed test and explain the business model of other speed tests and how the ISP prioritizes speed tests sites and how your site is the only accurate test around.

Then when your speed test gets popular. ISP's will think they're clever and start prioritizing your site!

That's when you BOOM! switch servers and point the DNS's to the new servers! Flip the servers running your business to the speed test servers and flip the speed test servers to your business!

Be sure to switch it back during off hours. Now you have a SUPER fast business operation and in addition to that a speed test site that is STILL more accurate then other speed test sites.

I've also noticed this, at least subjectively. I haven't done any rigorous experiments to confirm this is actually happening, but my ISP has a reputation for doing shady stuff, so it wouldn't surprise me if they prioritized traffic to speed test sites.

iperf is the gold standard for measuring throughput but it requires a shell on both ends.

The default TCP mode is fairly intuitive and usually gives a good idea of what is going on.

For precise independent tests of up and down speeds you need to use UDP mode with increasing bit rates until you start to see significant packet loss in that direction. Repeat in the other direction.

Another consideration is that the endpoint you are testing from (probably some cloud vm or server at work) will likely have different routing to your other endpoint (home) than other sites/services you visit. It is not unusual for eyeball ISP's to sometimes have congested peering with specific networks in specific locations while your work->home path will be clean.

Test it out by parallelizing a ton of downloads from a known good server and really overwhelm your connection. I find that it's not my ISP thats doing the throttling, its the content host at the other end. Steam/microsoft/even small third parties all throttle downloads after a while. If it was my ISP, I would see the throttling when I run my tester array on a server that I know for a fact doesn't throttle, but I don't, so its clearly the third party at the other end of the line trying to save money on upload costs. I can't blame them when everything is 4k now.

In my experience, OPs perception is generally correct, though perhaps less conspiratorial and nefarious than a reality of the system in place.

Across the many nodes between you and a destination, all sorts of traffic management systems move data around at different priorities. When something gets overloaded, stalled tabs are a visible system of the breakdown.

By initiating a large, typically sequential, high-speed transfer in both directions, you give each node an amount of time to recover, naturally move up the queue, and identify yourself as needing more resources. Once the speed test is moving along, everything else is 'along for the ride', to an extent.

On a home network, wifi aps are typically the biggest bottleneck, followed by underpowered or overheated routers/gateways. Depending on your isp's tech, there might be a bottleneck at a neighborhood hub, the central servers, their uplink, or more.

Anywhere along the way, this could be due to a mix of technical limits, high traffic, wear, negligence, incompetence, or intentional malice.

So you can assume your isp (or their isp) is throttling you in numerous ways. While some might be to deprioritize specific traffic or for political means, I think more is negligence, incompetence and under investment. When you identify yourself as someone needing more, or experiencing issues, it's in the isp's interest to silently resolve the issue automatically if possible (unless they think they can exploit it for a profit).

This is even more visible with the isp-owned speed tests, as you're naturally communicating to the fastest server available, plus they can shape the traffic and build the test to show you what they want you to see.

iPerf tests are a good tool for testing real world speed. As a basic tool, speedtest.net allows you to select from many test servers, often including your isp, a few local competitiors, and a close by university or tech company server. Individual numbers are less useful than a comparison between numerous tests and destinations.

A VM of smokeping or smokeping-speedtest is useful tool for monitoring these sorts of things as you can go back and look at what drops out when to get a feel conditions across the internet.

I test my speed by uploading/downloading huge files to my AWS instances. It always matches SpeedTest; I have centurylink fiber, it is >800Mbps up/down.

As others have said, if your destination has a slow connection, you're pretty screwed. Not to mention lots of slow file transfers = more latency impact.

Transferring 1x1GB file vs 1,000x1MB files is a HUGE difference, the latter will take much longer due to the initialization of the transfer. That's why we used to use FTP to transmit files instead of HTTP way back in the dialup days.

300mbit symmetrical fiber connection here. Even with a VPN (WireGuard), I can nearly saturate the downlink and uplink with a Speedtest and ~5ms latency. I get similar performance via sftp download from a server located several countries away. Upload speed is not nearly as good, but I can’t say if that’s due to my ISP or the server on the other end.

I’ve also seen a lot of Speedtest results for ATT fiber. These allow full gigabit transfers. I do wonder if these results hold up to actual use cases if someone can saturate 1gbit.

And I was thinking it was only me. I also noticed one more thing since last year: At times, my internet speed would feel stalled, so I check if my wireless connection is still ok. I open the wifi connection tray from the right hand corner and I notice that only my SSID is displayed. The moment I hover over my SSID, the other neighboring SSIDs and my other SSIDs(2G, 5G ones to which I am not connected to) appear suddenly. And 8 out of 10 times my speed gets a boost and everything starts working properly.

Both fast.com and speed.cloudflare.com give better results than speedtest.net, and now I'm concerned my ISP can't even be bothered to game the system.

For the curious, macOS Monterey includes a cool tool called `networkQuality` that does what you want. It checks the upload/download speed and more. Check out this[0] article or `man networkQuality` from your terminal

[0]https://www.macobserver.com/tips/macos-monterey-includes-net...

I believe it's because of burst technology and other QoS. It helps to have a burst of data ready for queue, but will throttle down over a sustained time. I believe this also helps overall network so that you do not continue sending in repeated same, say, from requested again over and over when the internet is slow / does not work adding to congestion.

Biggest improvement I found came from replacing the ISP provided modem/router with my own modem and router. Both improvements in overall speed and latency in gaming. I'm guessing they have less remote access control over third-party modems, and the quality of name brand is generally better. I use a Netgear cable modem and Ubiquiti router gear.

Have you tried using custom DNS (or an alternate provider) to attempt to bypass your ISP? Or run through a DNS (saw another comment saying to try a few different ones). Might just be slow all the time then (if they can't determine when to un-throttle your connection, ha). But at least you'd have something to look at.

I use https://speedof.me/ and https://testmy.net/. They match my QoS limits when QoS is enabled in my router, and match what I'm paying for when QoS is disabled.

I had this same exact thought, and will open fast.com once in a while to give my AT&T 1Gb fiber at home a kick.

But I never assumed malice, even if it is AT&T. I'm not a network engineer but I can see how giving whatever back end networking management system they have a nudge by requesting a fast connection improving things.

I dunno, man. I upgraded my 8 year old router and saw my speeds increase 100 fold on speed test. Thinking this was an aberration, I ran some tests doing software downloads and some DB backup restores that would give me enough testing time to rule out connection start friction or drops, and it was pretty much confirmed.

If you want more data points, configure your egress traffic to go through various VPNs to see whether you get the same results. It’s easy enough to do from a computer or a supported mobile device, if you’re willing to spend a few bucks trying a few different services out. I believe several of them offer free trials.

Whenever my comcast link gets slow I go to their speed test page and it always tries to tell me I'm getting more than what I'm paying for. Shortly after running the test everything starts to speed up again.

Makes me wonder if they have some kind of shady "squeaky wheel" QOS traffic shaping voodoo.

A twitch art vtuber steamer had a similar realization:

Running certain online games in the background (I think it was final fantasy) fixed problems with the art/drawing/just chatting stream dropping frames.

(Sorry I forget who, I also think it wasn't someone I normally watch so it's unlikely I will remember.)

Anecdotal, but I consistently get 80mbps on speed.cloudflare.com and 220mbps on fast.com with Spectrum.

I have to use my VPN to get any sort of performance. My isp throttles the shit out of everything, but they're usually a couple months behind my VPN provider, and when they catch up I switch. I just want the fucking service I pay for without the doodlefuckery.

I find malice difficult to believe.

Instead, I wonder if your router or something else on your network stack is a little wonky. Do speeds increase when you reboot your router or cable modem? When you have slow speeds, does another device on the network also suffer slow speeds?

When I lived in the Midwest I had frontier and when I’d complain about speeds they’d send me to their speed test that always reflected my exact data speed (even though the actual internet speeds were 10x slower some times.) Fast.com always had more accurate speeds.

The thing I keep getting suspicious about is occasionally network traffic will stop, I begin troubleshooting with a traceroute, and then coincidentally traffic will resume. It feels like the traceroute fixed the problem but it must just be my imagination. Right?

I have noticed that speed test seems to run fast when everything else is slow. I haven't seen anything else speed up though. I guess they prioritise traffic to speed test, but unfortunately that doesn't get me a speed up in general.

On Windows, Chrome is limited to one core when it’s in the background and uses all the cores in the foreground. Makes web development incredibly annoying. (This was several years ago, it might have changed and I don’t use windows as much)

Write a script to curl speedtest every minute and have fast internet speed all the time?

can confirm. used to work for an ISP and they game it, and the reason is that everyone else does. you aren't supposed to game the fcc broadband site, though, since they use they as a proxy for internet speeds in the US.

Ultimately it’s down to peering. Even without malicious action from your provider, it could just be that their routes to your selected speed test server are free while the routes to your other destination are congested.

Country, ISP?

I never noticed this with any ISP I've used in NL/DE/BE/FI.

It's possible even if ISP don't manage traffic, if you use VPN. After much traffic went by speedtest, TCP window size for VPN connection should become big that helps connection speed.

Note: Users in Sweden and northern Europe are probably better served by http://www.bredbandskollen.se/

I observed this as a kid and still experience it these days.

Never even questioned whether it was true because it felt so incredibly obvious that the ISP was dethrottling whenever they detected a speed test.

You can use iperf, for which many public server exist.

https://iperf.fr/iperf-servers.php

You mentioned Stalled Tabs. I am wondering if you have so many tabs opened the Network detected it as some malicious traffic and starting slowing you down.

Sounds like an opportunity to exploit for faster Internet speeds. Work out how they detect it and always have it thinking you are running a speed test.

That’s true. Whenever the internet seems too sluggish, I run fast.com and other internet speed test tool then everything seems significantly faster.

I've been using the networkQuality command on MacOS (a command line tool). It has a few interesting options so see its man page.

Speedtest is there to verify the PHY - shouldn’t be used for anything else. If you want to test “Internet” speed - use speed.cloudflare.com

I used to unfreeze my unresponsive safari and chrome tabs by opening Firefox. Worked most of the time. Any similar explanation or am I nuts?

It seems that fast.com overestimates your connection bandwidth if the tab you're running it on gets put in the background.

related question: spectrum pushes fiber where i am located, but there is no way to bring fiber into our residential unit/building. i guess they mean fiber to a local hub or something, then cable to our unit. isn’t that what they do anyway, and unless you have fiber into the unit, offers no improvement?

Where are you located? Never had this happen with the ISPs here but perhaps it's common in other countries.

So a shell script or browser extension that periodically curls speedtest sites would enable faster browsing?

So some ISPs are rigging the results like some car manufacturers were cheating on diesel eco tests?

google "speed test" also offers another view... but haha no less biased afaict.

speedtest.net: 19ms ping / 288 Mbps down / 72 Mbps up g speed test : 8ms ping / 620 Mbps down / 28 Mbps up

+1 - noticed the same thing twice last week. But naturally I thought I was just paranoid.

Xfinity?

Aren't this same as benchmark cheating? The ISP shall be banned

Welcome to the world of traffic shaping and QoS.

Download a steam game and check your speeds...

Yes, they've been doing this for years.

fast.com is pretty much the only one I use these days, since that uses Netflix’s servers.

So much for Net Neutrality ...

Use DoH. ESNI would help too.

if you are on a macOS, open up the command line and run networkQuality -s

Which ISP? Name and shame

Fascinating if true.

Did a little bit of data mining on this thread.

All Test Pages mentioned so far:

----------------------------------

https://www.speedtest.net/

https://www.speedtest.net/apps/cli

https://speed.cloudflare.com/

http://www.dslreports.com/speedtest

https://librespeed.org/

http://134.209.196.181:8080

https://proof.ovh.net/

https://fast.com/

https://speed.aussiebroadband.com.au/

https://www.speedcheck.org/

https://speedof.me/

https://testmy.net/

Additonal Sites not mentioned yet:

----------------------------------

https://speedtest.xfinity.com/

http://internethealthtest.org/

https://speedsmart.net/

Tools:

----------------------------------

https://iperf.fr/iperf-servers.php

https://github.com/orz811017/boost_bandwidth_via_speedtest

https://github.com/e7d/speedtest

https://www.bitwizard.nl/mtr/

https://github.com/tommie/chargen2p

https://github.com/tommie/prometheus-connectivity-exporter

All those ads...

That's true! Whenever I got test the speed of my internet, my WIFI goes up to 100mbps, but when I watch videos and stream on YT, it buffers a lot of times. Maybe because my router's kinda old? I'm not so sure tho.