DPC Latency Spikes

[Falcan]

I'm having problems with large DPC latency spikes (over 20,000 uS) whenever I open a new window or program, move windows around the screen, or basically do anything. This causes the entire computer to slow down for a second and audio to pop. The spikes will last for a second or so, then things will go back to normal ranges (green on DPC latency checker) until I do something.

LatencyMon points to USBPORT.SYS as the driver normally at the top of the execution time list. Sometimes there are others, but USBPORT.SYS is at the top 95% of the time.

I'm not sure what to do here. Last night I reinstalled Windows 7 (this computer is barely a week old), this didn't fix the problem but I did make the mistake of installing the Drivers on the Motherboard CD before testing. I'll reinstall Windows again tonight and test before doing anything else, but I don't have much hope that this will help.

Disabling the USB drivers in Device manager didn't help, nor did disabling the LAN driver (read that was a common cause).

What else can I try? Googling this issue was not much help, seems to be a somewhat common issue but not many of the threads I found had actual solutions.

Do I need to call Newegg/ASRock and get a new motherboard? I don't have any other parts to try swapping in new ones.


The only parts I feel reasonably confident are working ok are the Memory (passed a few hours of memtest86+) and the graphics card (problem didn't go away when switching to Onboard video).


Thanks for any help.


CPU: i5-3570k
MOBO: ASRock Z77 Extreme4
RAM: 8GB DDR3-1600 Corsair Vengeance
GPU: XFX DD Radeon 7950
PSU: 650W TX Corsair Enthusiast Bronze
Windows 7
Two Acer Monitors (DVI and DVI->HDMI connections)

 

[sm625]

clear cmos

 

[Falcan]

I just tried that, but it didn't help. I also noticed recently, today or yesterday, ASRock came out with a new bios (1.8), but this didn't help me either.

While the system is idle everything is fine, but as soon as I open a window I get a spike. Moving that window around also causes problems.

 

[Falcan]

EDIT: Well, I might have spoken to soon. I'm still getting a few spikes, less than before though. LatencyMon is reporting a high pagefault resolution time (100000 uS). What could be the cause of this?

Well I made some progress. I decided to uninstall the graphics drivers for what must be the 6th time. This time without them things worked. So I put them back on, things still worked. During this time I was only using one of my two monitors (I had tried using just one before, and it had not helped).

Plugging in the second monitor things went south again. It seems it does not matter which monitor is plugged into the graphics card (left or right), as soon as both are in at the same time, I get the DPC spikes when opening and moving windows.

Plugging both into the motherboard works fine.

So now it is looking like it's something wrong with the graphics card. I guess I'll call XFX support.

 

[bononos]

When you said you installed the drivers, did you install the full motherboard suite of s/w? I normally do not install those since they have been known to cause latency issues. Eg. the overclocking/temp/fan monitoring s/w.

 

[Falcan]

I installed only what was listed under Drivers. Not "Drivers and Utilities". Stuff like USB Drivers, LAN Driver, Integrated graphics driver, etc.

 

[Falcan]

Well I think I'v narrowed it down to a defective graphics card. My brother brought over an older Nvidia card (8800 GTS I think) and it didn't have any issues using the same slot on the Motherboard and the default Windows VGA drivers.

So now I'll have to see about getting a new card.