Ok I have been fighting this problem for almost a week now. I noticed my CPU was always at 40-60% usage, even when sitting idle. I did a little research and downloaded process explorer form the MS website. This is when I discovered that it was hardware interrupts that were using up my clock cycles. So how do i fix this? Well after a little more digging I found and downloaded a program called RATT, ran it, and looked for drivers with a high ISR count.

2010-5-5 System interrupts and High CPU usage. Hardware Interrupts are caused by hardware devices which are plugged. That is for windows vista not windows 7. High CPU consumption by these activities [interrupts and DPCs] can indicate a hardware problem or issues with the device driver.

It's my NDIS.sys and USBPORT.sys. So I disabled the drivers in Device manager to double check, and no CPU usage! So a simple reinstall of the drivers should fix it right? I first tried the latest ones from the Biostar site, no luck. Then I tried the one's that came on the disk. I finally got fed up, backed up everything and did a reformat-reinstall of windows.

After installing all the drivers, all was well. Well today when I turned my rig on, guess what? Same thing as before. Here are the relevant entries from RATT: Cumulative Histogram for: USBPORT.SYS ( SystemRoot system32 DRIVERS USBPORT.SYS) #, Range, Label, ISR Count, DPC Count, DPCTmr Count 0, 0.00us to 0.99us. Ok this is weird. I decided to try and put my wireless NIC from my folding rig in to see if that would solve the problem.

Well, i installed it, booted up, and went into BIOS to disable the integrated NIC. Booted windows up, realized i couldnt find my driver disk. So i shut back down, went into BIOS again to reenable integrated so i could connect to the net to get the wireless driver online. While i was in BIOS, i poked around the ICQ settings to see if anything was out of line.

I disabled the modem icq (or whatever it is, i cant recall at this exact moment), booted back into windows, then proceeded to reenable the ethernet driver. No jump in CPU usage. So i reenabled the USB driver as well. Still 0% usage. Well i guess the problem solved itself. Either disabling that modem setting did it, or there was just a lonely PCI slot.

One thing i did notice though. In the device manager before i rebooted this last time the integrated NIC was listed as 'Generic Marvell Yukon' whereas now it just says 'Marvell Yukon'. Ok this is weird. Beolink 7000 Service Manual. I decided to try and put my wireless NIC from my folding rig in to see if that would solve the problem.

Well, i installed it, booted up, and went into BIOS to disable the integrated NIC. Booted windows up, realized i couldnt find my driver disk. So i shut back down, went into BIOS again to reenable integrated so i could connect to the net to get the wireless driver online.

While i was in BIOS, i poked around the ICQ settings to see if anything was out of line. I disabled the modem icq (or whatever it is, i cant recall at this exact moment), booted back into windows, then proceeded to reenable the ethernet driver. No jump in CPU usage. So i reenabled the USB driver as well. Still 0% usage. Well i guess the problem solved itself. Either disabling that modem setting did it, or there was just a lonely PCI slot.

One thing i did notice though. In the device manager before i rebooted this last time the integrated NIC was listed as 'Generic Marvell Yukon' whereas now it just says 'Marvell Yukon' Weird stuff man, my RAID0 array was messed up not to long ago by the BIOS having incorrect SATA and RAID controller settings, no idea how they got that way.

I turned on my comp when i got home from work and the system hung at the post screen. So i tried the restart button, and it hung again.

So i turned the system off completely and back up and it got past post, but when windows came up, it was right back at 40-50%. Since my wireless card is still installed, i got the driver, installed it, then disabled my onboard ethernet. Still at 30%.

So i also disabled the standard enhanced pci to usb host controller and it dropped to 0%. So that's where i'm at now. Any suggestions anyone?