2 PCs connected to same modem, speeds vastly different

[residentisz]

Hi,

I just had AT&T Fiber 1000 plan (basically 940 up/down) installed, and I have 2 desktop PC connected directly into the modem.

PC "A" is my roommates running Windows 7
PC "B" is mine running Windows 10

my PC gets:
624MB down
17MB up

my roommate's PC gets:
706MB down
546MB up

oh, and my iPhone 10 gets 72MB down, 86MB up

Any idea why the UP would be so different and things to try to improve it on my PC?
I am doing the speedtests now with nothing but Google Chrome, Slack, Battle.net open.

The differences in down isn't a big issue but the UP is for when uploading YouTube videos.

thanks in advance for any help you can give me.

[Flame6]

Swap the cables and see if it changes.

[Temp name]

Swap the cables and see if it changes.

Cables are symmetrical, if you can get 600+ down you should be able to get 600+ up on the same one.

If you're using a bad network card, it might not be symmetrical though, but even then, 624 to 17 is a bit extreme.

[AIBot]

It will be a driver or program limiting it on your pc. Start disabling services.

[JustaWarlock]

Cables are symmetrical, if you can get 600+ down you should be able to get 600+ up on the same one.

No, damaged cables, wrong category cables or too long a run will all cause issues at gigabit. You can't universally say if you're getting 600 down you should be able to get 600 up.

OP, check that your network card is set to Full Duplex (it shouldn't allow anything else at 1Gig). Then check that your network cable is Cat5E at a minimum.. Finally, check that the various xxx offload options on your network card device properties are all on.

Also check your TCP stack tuning, especially RWIN and MTU.

[endorus]

iPhone
The 72Mb on the phone is "normal".
That is because your router/AP is operating on 2.4Ghz, likely using 20Mhz channel width and receiving 1 spatial stream on 802.11n standard this equals 72Mbps. 802.11n routers have 4 spatial streams of 40Mhz or 8 x 20Mhz If you could switch to using a 802.11ac router you will get ~8 x 80MHz which can be combined into 4 x 160MHz so each channel giving 8x the speed of what you're seeing now.

Theotetical max speed of a 160MHz channel is 866Mbps.

You iphone is 2x2 MIMO, so you should have 2 antenna capable of connecting simultaneously, I don't think an iPhone can handle 160MHz but you can certainly use 80MHz so your theoretical max speed is as above over 2 streams, 866Mbps.

In short, your wireless is shit, try a third party router and/or decent access points or see if it can be reconfigured as above.
I am with Virgin Media (UK) and we're given a Superhub (the relevance of the name is debatable) by standard the 2.4Ghz frequency operates with 20Mhz channel width, so were it not for my third party APs I would be in the same situation as you.

PCs
Modem > Cable > PC (Motherboard NIC?!)

Try the standard things as Tommys said above, swap the cable - retest, swap the port on the router - retest, are the results similar?

Do the speed tests with no other devices connected (the other PC off, no phones connected to wifi)

If after all that the tests are comparative to what you have done already, it could well be the NIC in your PC or the router...

Are you able to get into the AT&T router and see the sync speed?

Now I have to use the Virgin Superhub which i am 'forced' to use but you can put it into "modem mode" or "passthrough" mode and use a 3rd party router, I assume it is the same for AT&T, this might be a good option for you to get the most out of your connection for all devices. Disclaimer that I don't know what router AT&T gave you so can't comment to its quality.

Source: I work for a business telecoms company.

[JustaWarlock]

If after all that the tests are comparative to what you have done already, it could well be the NIC in your PC or the router...
Are you able to get into the AT&T router and see the sync speed?

How is half of what you said relevant? He is plugged into the same router as his roommate - obviously sync speed has nothing to do with anything considering the speed his roommate is getting. Same answer with the router - obviously if his roommate can achieve good line speeds the the router is capable of supplying it, so there's nothing wrong with it.

It's like you guys don't even read the question.

[js3915]

When you do a speedtest ideally you should have 0 other devices connected to the network, by the looks of it OP has 2 other devices.

If its a brand new device and your directly coming from the ATT router then low chance its an issue with the router, but anything is possible.

Not sure about ATT fiber routers but if its like their older ones you can log in see what its synced at.

If you disconnect everything but your PC run a speedtest and still see similar results its a cable issue or pc issue 9/10 times...

Course could be issue with the CPE, but low chance

[residentisz]

When you do a speedtest ideally you should have 0 other devices connected to the network, by the looks of it OP has 2 other devices.

If its a brand new device and your directly coming from the ATT router then low chance its an issue with the router, but anything is possible.

Not sure about ATT fiber routers but if its like their older ones you can log in see what its synced at.

If you disconnect everything but your PC run a speedtest and still see similar results its a cable issue or pc issue 9/10 times...

Course could be issue with the CPE, but low chance

yeah I've done the test with everything connected and with ONLY my PC connected and the speeds are almost identical.

I then tried my PS4 (which is always turned off unless I'm using it) and that even had 154 down, 122 up

- - - Updated - - -

No, damaged cables, wrong category cables or too long a run will all cause issues at gigabit. You can't universally say if you're getting 600 down you should be able to get 600 up.

OP, check that your network card is set to Full Duplex (it shouldn't allow anything else at 1Gig). Then check that your network cable is Cat5E at a minimum.. Finally, check that the various xxx offload options on your network card device properties are all on.

Also check your TCP stack tuning, especially RWIN and MTU.

thanks Justa, I'll check that stuff when I get home tonight.

re: length of cable, my cable is within 3 feet from the tower to the modem. My roommates is about 10-15 feet away.

[markos82]

Could be different bandwidth allocation on Win7 compared to Win10

[Hoofey]

You got the motherboard chipset\network drivers installed right?

Updating that stuff might be a good place to start.

[residentisz]

You got the motherboard chipset\network drivers installed right?

Updating that stuff might be a good place to start.

yeah that was first thing i thought of too, but all my drivers are up to date. I use the paid version of Driver Booster Pro 6 for it

[endorus]

How is half of what you said relevant? He is plugged into the same router as his roommate - obviously sync speed has nothing to do with anything considering the speed his roommate is getting. Same answer with the router - obviously if his roommate can achieve good line speeds the the router is capable of supplying it, so there's nothing wrong with it.

It's like you guys don't even read the question.

Because I'd like to see his sync speed?

Secondly, as js3915 said, the speed test should be done with no other devices. The sync speed would then show how much of the actual speed is being received as throughput compared to the speedtest. The difference can indicate many potential issues. Now given that we don't know what the modem is in sync at we don't know that his mates PC is getting the full speed, we need a marker to work toward.

So yes, all of what I've said is relevant because it's part of basic diagnostics, work backward. Now since then, some of that has been confirmed by OP.

PDNTSPA

If you can rule out modem(1,2), Cable(1) Router(3), drivers(2 llc), AV/firewall(3,4), malware (4-7) etc then the issue can only lie in settings or applications (speedtest) given you have multiple similar results, I'd guess the former.

in CMD run; netsh interface tcp show global

Does "Receive Window Auto-Tuning Level" show "Normal" or "Disabled?
If "Disabled" enter; netsh interface tcp set global autotuninglevel=normal

Re-test, does that improve?

If its already normal then we'll have to look for bandwidth hogs or at the NIC.

Justa raises a valid point with the TCP stack so check that.

I would also look at doing an iperf between you and your mates PC to rule out the NIC if you can't find anything wrong with the settings. Because whilst we don't know the maximum speed you can receive at the WAN, we can test it over the LAN knowing your friend can upload at least 546 and down 706 both of which are higher than your results meaning we might see you throttle if it is indeed a PC issue.

As to the phone speed, if you can log into the router and change the channel width to 40Mhz you will see improvements. If you can set a 5Ghz network on 80Mhz and lock your phone to it (settings in phone) you will see substantial gains.

[JustaWarlock]

Because I'd like to see his sync speed?

Secondly, as js3915 said, the speed test should be done with no other devices. The sync speed would then show how much of the actual speed is being received as throughput compared to the speedtest.

No, it was completely irrelevant, you seem fixated on his download speed when even the OP said he didn't really care about it. If you had read his question wasn't anything to do with "am I getting the correct download speed for my sync" it was effectively "why am I getting 17MB up on my PC when my room mate is getting 546MB up from the same router".

When there's a 32x loss of upload speed on one PC, it's unlikely to be anything to do with the router and much more likely to be a physical problem foremost, or less likely the other things I mentioned.

All of the advice you have given isn't bad advice, especially the netstack tuning, it's just bad advice in the context of the OP's actual stated problem.

[endorus]

No, it was completely irrelevant, you seem fixated on his download speed when even the OP said he didn't really care about it. If you had read his question wasn't anything to do with "am I getting the correct download speed for my sync" it was effectively "why am I getting 17MB up on my PC when my room mate is getting 546MB up from the same router".

When there's a 32x loss of upload speed on one PC, it's unlikely to be anything to do with the router and much more likely to be a physical problem foremost, or less likely the other things I mentioned.

All of the advice you have given isn't bad advice, especially the netstack tuning, it's just bad advice in the context of the OP's actual stated problem.

OK, thanks for your opinion.

[js3915]

yeah I've done the test with everything connected and with ONLY my PC connected and the speeds are almost identical.

I then tried my PS4 (which is always turned off unless I'm using it) and that even had 154 down, 122 up

Well, same results I suppose you should just verify though Windows 10 Task Manager that nothing is indeed is NOT using any bandwidth at least in the upload direction.. Like maybe Google drive is sending a shit ton of files upload causing your results to look so bad? Id say thats low probability but a possibility but something easy to rule out.

Also ensure you dont have any weird networking boosting software installed... I seen some by doing some google searching that this was causing the issue

Another suggestion is to disable IPV6... Worth a shot

https://answers.microsoft.com/en-us/...f-1f2a35ec053c

[residentisz]

Also check your TCP stack tuning, especially RWIN and MTU.

thanks man!! I googled how to do that and found speedguide.net where it had a TCP Optimizer. I ran that, adjusted the speed and BOOM!!

now I got 917 down and 468 up, okay still not perfect but i'll take it, light years better than the 17 i was getting prior.