When downloading a large file I find that the download speeds up dramatically during a speed test:
First the download reports that it will take 9 hours to complete:
Next I start the speed test and almost immediately the download speed increases dramatically. Especially during the upload phase of the test:
Finally, after the speed test the download almost comes to a stop again:
I actually have to run the speed test a second time to force the download to complete.
I am very puzzled by this. At first I thought it was because I had a new router installed, namely the PACE 5268AC, because before that I had the internet cut out once or twice every other day, but I don't remember the downloads being slow. After that I found that I struggled sometimes just to get web pages to load.
After some long calls with technical support I decided to get Xfinity installed for a side by side comparison. Today is the first day I have both and to my horror (or relief depending on how you look at it) I found the same symptom with the Xfinity connection.
I have a wired connection from my PC to the router. My UVerse plan is 1000Mbs and my Xfinity is 250Mbs. Both do well on the speed tests but struggle on the large downloads unless I have the speed test running. I even booted into Linux and did the same speed tests and downloads from Linux and found the same behavior. So at this point I am willing to believe it is my PC that is doing something that results in the slow download of files.
I tried from a laptop via wifi and found that the download speed is higher (even though the speed test is much lower of course).
Does anyone else have a similar experience? I'm now learning about things like buffer bloat and I wonder if perhaps I'm seeing this symptom because my PC is 'too fast' for the upstream network and having a speed test saturate the connection is indirectly alleviating symptoms. Perhaps the old UVerse router was slower in some respects and that was ironically helping?
The slow downloads on my PC are driving me nuts, especially after I remember them being fast before. The main question remains; how can the speed test be so fast and the download be so slow without a running speed test?
I have determined that there is something going on with the Intel network interface. I have an Intel(R) Ethernet Connection (2) I218-V built into the Asus X99-A motherboard. If I change the speed to 100Mbs full duplex then I get much faster downloads, but now the speed test result is lower and the downloads are capped at 100Mbs of the 1000Mbs I should be able to get.
Turns out it was the EEE (energy efficient ethernet) setting for the NIC that for some reason resulted in the slow speeds for gigabit connections. Deselecting it fixed the problem. I had to install the intel driver to get all the settable options.