A friend of mine has an old AMD K6-2 550 system and I installed a new hard drive for him. A Maxtor ATA100 20 GB HD. The hard drive is detected at UDMA 4 (ATA66 I believe) by the motherboard and everything is fine, but windows detects it as PIO mode 4 and not even as UDMA/33 or even regular DMA. He has an AT PCChips motherboard with integrated video and sound with the SIS 530/5595 chipset. I don't remembet the exact model. All with the latest bios. I checked and XP is set to use DMA if available but still only uses PIO 4 which makes his system very slow as HD acceses easily eat up a large portion of the CPU time. I need to know how to force XP to use DMA, any DMA even if not UDMA if at all possible.