Windows 7 - Network usage causes high DPC Latency

Yes, disabling the network adapter resolves the issue, but I've tried several different adapters, including two integrated adapters in the two different mobo's that I've tried, and a usb-based adapter, so the issue is not a specific adapter, but rather something in the OS that is related to the adapter.

Thanks for the reply though!

Ah, got it. That is frustrating...

Add me...

I also tried external / internal sound cards, did not help.

If changing drivers and / or hardware does not change the problem, it should be a Windows 7 problem, right?

BTW, to get the latency into the green, it is sufficient for me to deactivate the network adapter and activate it again. It needs some time for the system to stabilize, but then the sound is fine until I start to actually use the network again. Surfing, downloading will bring me back into the reds within a few seconds. I'm testing if lowering the concurrent connections lowers also the lag... seems like

Welcome the the club of woe! I've replaced every component in my system except the CPU (yes, I even replaced the mother board!), so it's either a problem in the OS or in the CPU, and I still have the same issue.

My CPU is a Intel Quad CPU Q8200 @ 2.33GHz. I wonder if we should poll people with this problem to see if it's a CPU issue.

Your comment gave me the idea to try with a different OS (since I don't have another CPU).
I started a virtual machine (Windows Vurtual PC) with Windows XP installed. I setup a bittorrent client and downloaded open office. If I'd do that in the host machine, I'd have latencies about more than 100000 µs, doing that on the virtual PC, I have a maximum of 1600 µs!

With that, I am sure that it is a OS problem in Windows 7.

I have the exact same problem and started googling around found this thread.
I had the same happen: very high latency when downloading at high ~100Mbps speeds using utorrent.
And behold I solved the problem! Updated utorrent from 1.8.5 to the latest 2.0.4 (Build 21586). Also i unticked "Disable windows caching of disk writes/reads" from disk cache options. And now the lag is gone I'm not sure unticking the settings were the key, but I wont dare to touch anything now. It would make sense, that having windows caching disable could cause an immense amount of interrupts.

I "unticked" it too and had no lag for 5 seconds, then back to the previous high lag.

Why should disable caching cause interrupts???

Good luck getting this resolved. I gave up on my system after replacing every component including the motherboard and Power Supply. So I foolishly went out and bought a new computer. An HP HPE-150f running Windows 7 x64. Guess what? Exactly the same problem. The only common factor is Windows 7 x64. The only workaround is to reboot the computer several times a day.

Or try a different OS, like Win 7 32-bit, XP, or Linux.

I tried Microsoft's Windows Performance Toolkit to isolate with xperf.exe which driver is causing the lag... it was
<drumroll>
Microsoft's ndis.sys
Since it is related to network traffic, I'll try it with a different (better) network adapter.. I don't have much hope but I'm willing to give it a try.

In may case, it was really NIC driver related. After chasing this issue with Windows Performance Analyzer, I came to conclusion that high DPC is related to my Atheros 8121 driver.

My mobo manufacturer Asus is not very vivid on updating their support site unfortunately, so I found latest Atheros AR8121/AR8113/AR8114 drivers at: Atheros Communications

Only version 1.0.0.49+ is fixing this issue; I have now my machine with filesharing for days running and crated lots of traffic. All fine, DPC Latency Checker still shows green and low bars!