Gigabit LAN Download Speed Much Slower Than Upload

jhumur · 26 May 2017

Three weeks ago, I had Gigabit FIOS installed, but I have never been able to get gigabit speeds going both ways. I always get 900+ Mbps UPLOAD but never more than 300 Mbps DOWNLOAD.

But, I get 900/900+ Mbps between the Router and the Server every time, *AND*, here's the real kicker: I get 900/900 Mbps from the desktop if I run in Safe Mode. So, I've concluded that it's not a downstream hardware or a FiOS server issue, but rather something to do with my onboard LAN setup.

I have tried the obvious things: (1) Different Ethernet drivers from Microsoft, Realtek, and ASRock; (2) Different cables (CAT5e); (3) Played around with Adapter settings such as "Receive Buffers" (512) and "Speed & Duplex" (1.0 Gbps Full-Duplex). None of this has helped. I am running Win 10 Pro 64-bit.

So I guess what I am asking is: What do you think it means that I can make Gigabit FIOS work in Safe Mode but not from the normal desktop? Hoping you could give me some guidance on where to look for the culprit.

Genuinely, thank you for your help!

WOT · 26 May 2017

jhumur said:

I get 900/900 Mbps from the desktop if I run in Safe Mode.

Is that safe mode with networking? Is that 900/900 throughput from/to FIOS?

jhumur · 26 May 2017

WOT said:

Is that safe mode with networking? Is that 900/900 throughput from/to FIOS?

Yes, sorry, I should have made it clearer. It's with Networking and the 900/900 throughput is from the desktop to the FIOS server and back.

WOT · 26 May 2017

OK, then it is definitely a problem with a driver, service, or program on you PC that is not being started in safe mode. The first two drivers that come to my mind are the graphics driver and the network adapter driver, Now, I'm fairly certain that a default graphics driver is loaded but I'm not sure about the network adapter driver. So, how could a graphics driver be the cause? Who knows, but try it anyway. This is just a starting point for your research and you may have to continue to do this comparing (eg, normal mode vs safe mode) to try and isolate the cause. I have to sign off for tonight but hopefully someone else will chime in to help you.

jhumur · 26 May 2017

WOT said:

OK, then it is definitely a problem with a driver, service, or program on you PC that is not being started in safe mode...

This is insane! My security software are what's killing the speed. With Malwarebytes running by itself, I take a 300 Mbps hit. With Kaspersky Internet Security running, I take a 600 Mbps hit. (And it doesn't matter then if Malwarebytes is running or not.) So there you have it, the 2/3 drop in speed is due to KIS. Ridiculous. I don't know what the solution is, but I'll come back and update the post when I do figure it out. BTW, thanks for kicking the cobwebs out of my head. Without your help, I'd still be floundering!

cereberus · 27 May 2017

Well obvious thing to try is see what happens when using defender with others disabled?

WOT · 27 May 2017

jhumur said:

This is insane! My security software are what's killing the speed. With Malwarebytes running by itself, I take a 300 Mbps hit. With Kaspersky Internet Security running, I take a 600 Mbps hit. (And it doesn't matter then if Malwarebytes is running or not.) So there you have it, the 2/3 drop in speed is due to KIS. Ridiculous. I don't know what the solution is, but I'll come back and update the post when I do figure it out. BTW, thanks for kicking the cobwebs out of my head. Without your help, I'd still be floundering!

You are quite welcome. Glad we could help. In addition to the recommendation by @cereberus, you could also try a lighter-weight AV solution. I use Avast Free and I do not suffer any throughput loss when connecting to my ISP. FYI, you could also use Defender and Avast together now because both have the ability to act as secondary "on-demand" scanners while co-existing with a primary AV solution.

Cheers,

WOT

jhumur · 27 May 2017

cereberus said:

Well obvious thing to try is see what happens when using defender with others disabled?

Yes, that would seem to be an obvious thing to try, but I'm not that clever.

I will now tho.

jhumur · 27 May 2017

WOT said:

You are quite welcome. Glad we could help. In addition to the recommendation by @cereberus, you could also try a lighter-weight AV solution. I use Avast Free and I do not suffer any throughput loss when connecting to my ISP. FYI, you could also use Defender and Avast together now because both have the ability to act as secondary "on-demand" scanners while co-existing with a primary AV solution.

Cheers,

WOT

Thank you, man. I'll uninstall KIS and try out Avast. I'll report back with my findings.

WOT · 27 May 2017

A tip when installing Avast Free:

Select a custom installation:
Watch out for the first screen that has a tick box at the bottom to install Chrome, uncheck it.
As you progress, you will encounter a ton of options already check-marked for installation.
On my rig, I only installed the 4 shields and unchecked the rest.
At the end, don't forget to register. It is really simple. Just a few clicks and you are done.
(enter no thanks to offers).
Just watch every screen carefully as you go.

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