I have been having problems with high DPS/IR CPU usage, I tracked it down to be related to network both downloading on network wifi and transferring files in and out of computer via USB... I was told too use some software a while ago that checks and the process causing he problems was NDIS.SYS, I tried Windows XP on the same laptop and the problem was gone, this seems to be an ongoing issue with windows 7, many other people have suffered with it, i seen many on other forums with same problem and not getting any answers, I think its about time Microsoft acknowledged this problem and sorted it, when I download at full speed of 1.8MB/s over wifi i get DPC usage of 5-15% (this is on a 1.8Ghz dual-core chip) - on LAN i get 1-5% - if I send files to usb drive and download over wifi I can get upto 40% CPU usage on DPC/IR.... surely, this is not normal operation? like I say the problem does not exist in XP , programs like LatencyMon point to NDIS.SYS

I found this elsewhere; not sure whether it could be helpful with your problem, but the user claims to have found a fix... http://social.microsoft.com/forums/en-US/whssoftware/thread/e988e172-a522-4666-8818-f17672571fd6 OK I've fixed it I found that WHS has downgraded one of my drives to use PIO Transfer Mode (Device Manager -> IDE ATA/ATAPI COntrollers -> Secondary IDE Channel -> Proprties -> Advanced Settings). This apparently happens is Windows encounters errors on a drive. I used Device Manager to Uninstall the Secondary IDE Channel, then rebooted to force Windows to re-install the Secondary IDE Channel. Bingo! It is now operating under Ultra DMA 5 mode. -Noel

Depending on the network adapter chip CPU load will vary. Better adapters have a CPU on them to handle the Ethernet frames and error correction etc. Cheaper ones do not. Windows MVP, XP, Vista, 7. Expanding into Windows Server 2008 R2, SQL Server, SharePoint etc. My page on Video Card Problems is now my most popular landing page. My Page on SSD is now #2. See my gaming site for game reviews etc. Developer | Windows IT | Chess | Economics | Hardcore Games | Vegan Advocate | PC Reviews