I'm having some issues with one of my PCs again. I was having problems with stuttering in DCS BS2 and Arma2, so I switched to a spare Win7 x64 install on my HDD with less stuff installed.
The latency hovers around the 100us mark with occasional spikes of 150-200 and sometimes I seem to be able to get it to stay more in the 20-50us range but I can't find a consistent method of doing this. One time killing nusb3mon.exe seemed to do it but another time didn't seem to have any effect.
My main concern is that I keep getting USBPORT.sys showing up as the highest DPC routine execution time (sometimes the ISR as well) with very high spikes, like 1500us. I've just killed TVService.exe which is the service for Mediaportal and that seems to have stopped that but obviously I need that running to record and watch TV (and clearly when watching TV, or any video, I don't want latency problems). My TV Tuner (Hauppauge Nova-T 500) does work on the USB bus, despite being a PCI card, so that sort of makes sense but I didn't see this problem on my other Win7 x64 install.
I haven't installed the AMD SB drivers yet, mainly because when I did on my other PC it would no longer boot, just BSOD, so I'm a bit nervous but can make a True Image before doing so if you think that might help. So it's just using the Microsoft AHCI drivers at the moment.
EDIT: Just realised I was using an old version of LatencyMon. Updated now and the latency's showing below 25us most of the time with highest 41ms, so I guess it must be measured differently. I'll try restarting TVservice.exe and see if it's OK now.
Nope, after restarting LatencyMon it soon had a DPC spike on USBPORT.sys of 1263us. There's higher spikes on the latency as well, highest 108us, some 50, 70, 90.
Edited by doveman, 01 September 2012 - 09:11 AM.