I just wanted to put my two cents in here for what it's worth. First of all, I have no interest in any online speed test. I host mirrors for the two most popular speed test sites, one of which you are on right now. My only interest is in helping people get accurate and informed information when it comes to measuring their internet speed. I will probably upset some people with this post, but what I am saying comes from my 12+ years of experience in tweaking web servers and meticulously measuring the details of different transports.
For http (e.g. "internet" or web-browser compatible) speed testing, I can say with 100% certainty that you will not find a testing methodology more accurate than testmy.net. The attention to detail and every little tidbit of information involved in http/tcp transport is second to none. I can say that since I host a mirror on here and can measure the results from both ends. For example, if you make a request on my box, apache keeps a log of the transfer information and precisely how long the socket was open and how much information (exactly) was transferred. The timing is accurate to less than 1/10000 of a second. Therefore, I can measure the precise time it took to transfer, say 100MB from my box to your computer and determine from that the speed in which the transfer took place.
TMN goes a bit further than most, in that you can see the actual speeds during the xfer as it fluctuates. The other speed test engines take an average of your speed over the duration of xfer and throw away a significant amount of the data as "erroneous." My question is, if it is erroneous yet contributes to the overall time it takes to transfer a file, it is NOT erroneous and should NOT be discarded as such. This is where you will see significant differences on the "other" sites.
Sometimes it is disappointing to see the real numbers your machine is capable of. Believe me, I know. I get upset when I think a measurement is wrong. But, it gives me valuable insight into how to increase the throughput and achieve better results.
Take a look at my max and averages
These come from my VNC (e.g. linux remote desktop) connections to one of my boxes using Firefox or other browsers to test the box. The average has been skewed by testing all kinds of different settings (e.g. jumbo frames, different MTUs, browsers, servers, etc) and so could be much higher if I dedicated an account singly to testing with my best settings...but that would kind of defeat the purpose, in my opinion! If you consider the overhead on the processor and network interface just to support my 1920x1080 VNC connection, then factor in that I am remoting into a server to test it's connection; furthermore that it is just a TCP link with limited threads that can be opened (due to the nature of the protocol), my box is capable of much more. But when it comes to true INTERNET ability, I have never measured anything faster than I can through testmy.net. Consider that the "other" sites use Flash and other visual enhancements, a limited amount of data and basically, nondiscriminatly discards data assumed to be erroneous, which site do you think will be more accurate?
I will soon be starting a blog regarding how to improve you internet connection speed and will post the link when I publish it. I would like people to try before and after modifying system settings as well as the other speed test sites. I say everyone should try the other sites as well and see where the discrepancy lies. But if you are truly looking to improve your performance, in my opinion, you have found the spot (that is, unless you want to write your own code and try to start from scratch what has taken a decade to get where it is...good luck by the way).
Anyone with questions, please feel free to ask. Understand, please, that I am often distracted and cannot immediately reply -- but I will reply. Probably your best source of information is in the threads on this site, or directly from Damon. He is very active on his site and generally answers anyones questions or posts fairly rapidly.
Thanks for reading and forgive my spelling and/or rambling! Good luck!
