Hi there all! This problem I'm having also occured under Windows Xp 32-bit. It's been pestering me since forever! Here's the issue: I have several HDDs installed in my system. They have been of various brandnames and sizes, constantly upgraded in time, changed HDDs with others and so on. So it really doesn't matter which HDds I currently have, but I'll tell anyway. The OS HDD is a Samsung SpinPoint 1612, ATA 133, 160 GB. The second HDD is a Samsung SpinPoint SATAII, 160 GB and I have an external USB2.0 HDD which is a 40 GB Maxtor, mainly used for data transfer. Whenever I copy a large file from one partition to another or from a HDD to another, the OS slows down more and more, until it comes to a point where I cannot do anything, the HDDs crunch data like crazy and I wait literally minutes to even swith from a window to another or to pop out the Start menu. The transfer speed (checked with Total Commander) drops to a petty 700-800 KB/s and the HDDs crunch and crunch and crunch... paradoxically, if I limit the transfer speed (with Total Commander) to 16 MB/s, the copying goes just fine. The transfer rate caps at 16MB/s and I can work with the OS. I've installed Sysinternals' Process Explorer to check what exactly is transferring data but got no clue. Sometimes, the OS HDD starts working, it crunches data and Process Explorer tells me there's no disk activity Indexing Service is disabled, System Restore is disabled, and I noticed the cache size increases to huge amounts during large file copying. Apparently, Windows moves runing software data from memory to swap to make room for the files I'm copying, which, I'd like to say, is the dumbest thing I've ever seen. The question is, how do I stop Windows from doing that (except from installing Linux, of course, which works just fine BTW)? Thank you in advance!