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Windows 7: Mysterious latency in Windows

17 Feb 2011   #1

Windows 7 Home Premium 64 bit
Mysterious latency in Windows

Hey all, first time poster here I'm sorry if this post is in the wrong section, but here goes:

Like the title states, I'm having a problem with latency issues since my last reinstall of Windows 7 (64 bit, Home Premium). When I'm running the DPC Latency Checker program, the values go between 150s to around 800s, just idling in Windows. Occasionally, or sometimes all at once, I get some very high latency peaks - from 3000s up to 17000s (my highest 'record'). I have some 'extreme' screenshots, where the latency is around 6000s for more than 30 seconds.

What really bothers me is that applications are slow to start, despite how well the latency meter is in the DPC Latency Checker application.

When I get the peaks, I don't see any increased CPU usage, or anything else for that matter, except in the Network graph in the Resource Monitor. The network usage spikes in the same manner as the Latency Checker program, which seems very strange to me. In the TCP connections graph I see as I write this, almost 100 connections. I had just 6 connections about 5 minutes ago.. And now, 1 minute later, it's back to around 50 - which is still high! Few minutes later it's around 8.

Two strange observations : The problem doesn't go away with the network disabled, though it's better. And I don't feel this problem at all in any game.

I simply can't make any sense of this. I hope there are some clever people out there, who's able to help me

Thanks in advance!

Edit: Just checked the connections that are actually running, there seems to be many connections that involve firefox.exe, and AvastSvc.exe. Whatever that means!

My System SpecsSystem Spec

17 Feb 2011   #2

Windows Server 2008 R2

If you disable the network card from ncpa.cpl (not pull the cable, but actually disable the NIC) does the problem continue?
My System SpecsSystem Spec
17 Feb 2011   #3

Windows 7 Home Premium 64 bit

Thanks for the reply!

The spiking seems to be about the same after disabling the connection. The connections clean up nicely after a minute or so though.

What I experience when I disable or enable the networks card, is that the latency peaks are so high (up to 16000 s), that I can hear it in my music that I'm playing on the computer. It makes some popping sounds and brief stops before stabilizing again, sort of.

The spikes in latency that I monitor in the DPC program aren't consistent either, sometimes it takes minutes between each one, sometimes 15 seconds, sometimes its each 2-5 seconds, or it's each second (each reading is one second apart). It somewhat seems related to if I have my browser open, but then, it's still inconsistent. The constant high latency readings seem to happen when the resource monitor displays an abnormal amount of TCP connections (50, or even 100+), of which the majority are firefox.exe and AvastSvc.exe connections. Many of them are listed as 'IPv4 Loopback' as remote address.

Additionally, when it's bad, I see a lot of connections without a process name, simple listed as a " - ", connected through the remote port 80.

Maybe this was just simply a bad install of Windows, as I right from the start this time have had trouble accessing files and folders on my computer, because of 'missing permissions' - which I never had as a problem before.
My System SpecsSystem Spec

18 Feb 2011   #4
Microsoft MVP


Try wiping the HD to clean reinstall, then try IE8 for awhile as it is finally perfect with 8 and more stable I've found. Try also MSE for a change.

Here are tips for getting a purrfect reinstall - use the ones which apply: re-install windows 7
My System SpecsSystem Spec
18 Feb 2011   #5

Windows 7 Home Premium 64 bit

I will try with a wipe of the HD, although it's going to take a while backing up all my stuff - Hopefully that will fix it.

Will report back later
My System SpecsSystem Spec
18 Feb 2011   #6

Windows Server 2008 R2

Good luck. If disabling the NIC didn't clear it up, then it was likely a driver loaded on the network stack as a TDI driver (antivirus, antimalware, 3rd party firewalls, etc) that would cause it. My money would have been on Avast, but that's just an educated guess.
My System SpecsSystem Spec
19 Feb 2011   #7

Windows 7 Home Premium 64 bit

I am now back after backing up all my stuff and after a total wipe of the harddrive. To be sure, I removed all partitions and recreated them again.

I just checked this moment with the latency checker - while it's far better now, I get occasional peaks, though much less frequent and the worst peak I had was a reading of 3400. The average peak is now around 1800, instead of 4000. Now I wonder if it's normal with peaks every 30 seconds / every few minutes? Can anyone help me figure this out? Anyways, the sound delay I had in Windows is now gone, every sound comes when it should, and not 3 seconds later!

I didn't do this the best way I could have though, as I installed Skype and Firefox before getting the latency checker. Silly me!

Studying the resource monitor, Skype can really open an abnormal amount of TCP connections! With this clean install, I saw up to 50 connections total, although it normally varies to be around 8-12 with Skype open.

Anyways, my main problem, which was the delay in sound and slow applications, seems to be gone now. I will try install everything that I usually do and see if it stays the same

As soon as I installed Avast!, the amount of TCP connections skyrocketed. I never thought an antivirus program could do that.. Hmm!
My System SpecsSystem Spec
19 Feb 2011   #8
Microsoft MVP


Follow the suggestion to switch to MSE as it is interchangeable with same quality yet often can avert problems the other one might encounter on a particular install.

This has worked about two dozen times on hundreds of installs, which is why I suggested it.
My System SpecsSystem Spec
19 Feb 2011   #9

Windows 7 Home Premium 64 bit

Yes sorry about that. I'll try that one right away!
My System SpecsSystem Spec

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