Hardware interrupts spiking

I must confess I don't understand what the hardware interrupts displayed in Process Explorer are and how they work. I'd like to know if it's normal for hardware interrupts to ever spike to 50% levels (this is on a dual core system, so it's probably taking one of the cores to 100% CPU usage)? I recently noticed that this would happen when I was using a program to compare a large amount of files on DVD to the same files on HDD. The program, I think, counts hashes of files both on HDD and DVD and compares the hashes. Should something like this cause hardware interrupts to spike like that, or is it abnormal?

In general, I'd like to know what would cause hardware interrupts and how much CPU they'd normally take. TIA. :)

Thanks, I'll check if it's in PIO mode and try that solution if it is. It's a new system, though, and I don't really like the idea it would just revert to PIO mode on its own. Broken hardware? I kind of hope not, seeing how new the system is.

Is it ever normal to see hardware interrupts take a notable amount of CPU time? Or does it always imply some kind of a software/hardware issue?

Edit: one more thing, this is an XP SP 2 system.


Edited by Buggy Buddha - 05 September 2006 at 6:33am

I see. I read that from the manual, but didn't quite understand whether it's always abnormal to see high CPU consumption by hardware interrupts or if it can even be expected in certain normal situations. Comparing the hashes of files has to stress the CPU, memory, and the hard drive and DVD drive alike, right? The program that did the hashing showed practically no CPU usage during the operation, but hardware interrupts stayed high. Originally, I thought it made sense, since the system was reading a lot of files from the HDD and DVD at the same time. The operation completed, too, and I didn't notice any system slowdown, though that may be just because it's a dual core system. But it'll be interesting to see if one of the devices has gone to PIO mode. If it hasn't, then it's indicative of an actual hardware failure, then? 

Edited by Buggy Buddha - 05 September 2006 at 6:45am

Looks like you were absolutely right. I checked the controller properties, and according to that, the DVD drive is in fact running in PIO mode. Windows even gave a nice warning in that menu, explaining that: "The transfer mode for this device was set to a mode lower than what it is capable of because of excessive transfer errors to that device. This will cause a loss of system performance. Please check the cabling to the device..." Nice. Going to set it back to Ultra DMA 2 mode and reboot. That does leave me to wonder what caused it to revert to PIO mode in the first place, though.

@Icon: Open a new thread in the Troubleshooting forum for your problem. If the interrupts are pretty much constant - i.e. don't only occur during I/O - then one would suspect an issue with sound/video, possibly a driver problem.