Windows Process DMA (Direct memory access) on Hard-Drives And CD-Roms in default For devices ATA or ATAPI (IDE) but other computer change to PIO mode that can move data in slow speed than computer that use DMA mode. It's Virus.
How To Do In Windows XP
Right click on My Computer -> Click on Manage -> Click Device Manager
Double click on IDE ATA/ATAPI Controllers
Right click on Primary Channel -> choice Properties -> Click on Advanced Settings
in Transfer Mode please click on drop-down box ->choice DMA if Available (if current setting is PIO Only)
Click on OK button
Note : DMA has in Windows Vista/7 also but it's just different in clicking.
