Speedtest different results for international servers

thecooldean · Aug 6, 2020

I’m having 250 Mbps plan from ACT and on my iPhone Speedtest app I’m getting high speeds to international servers whereas to the same servers on my PC, I’m getting a maximum of 10 - 12 Mbps, what could be the issue behind this?

I’ve attached a sample Speedtest from my iPhone where I get high speeds but to the same server on my PC I get ~8 Mbps.

thecooldean · Aug 8, 2020

Issue has been fixed after 4 years of staying in the dark. It had to do with TCP window size.

rajil.s · Aug 8, 2020

@TheCoolDean What window size are you using?

I bandaged my issue by changing the congestion algorithm.

thecooldean · Aug 9, 2020

@rajil.s For some reason the TCP receiving window was disabled (most likely due to a windows update in 2016), after 4 years of being unable to resoIve this, I just had to set it to normal. For more details kindly refer to this thread - [SOLVED] - Different Speedtest results on iPhone compared to PC?

I couldn't find any commands to alter window size, kindly let me know if you know how to do it.

rajil.s · Aug 9, 2020

Setting a tcp window size is pretty straightforward. However, finding the right window size is tricky.

thecooldean · Aug 9, 2020

@rajil.s any idea how to do this on windows 10 using command prompt?

rajil.s · Aug 9, 2020

Sorry, no idea. I don't use windows.

Speedtest different results for international servers

thecooldean

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