Hi folks My HD and DVD ROM are stuck in PIO mode. I recently installed WinXP with sp1 on a 500mHz Celeron PC with a SiS 620/5595 chipset. This chipset is capable of supporting UDMA. The hard disk and DVD ROM are both UDMA capable. (I installed the drives into another PC to double check, and they were UDMA all the way). Unfortunately in my system the drives both show that the transfer mode is PIO – and SLOW (esp. jerky DVD playback). - SiS recommends using OS drivers for IDE (I am) - I am using 80 wire ribbons. - I have tried BIOS settings for both IDE channels set to [AUTO] or [UDMA 2] as well as setting the transfer mode in the Device Manager to [DMA if avail] - I have each drive jumpered to master and at the end of it’s ribbon - Each drive is on it's own channel (no other devices on either channel) - The problem exists on clean OS install so it’s not a repeated error problem - - I have tried the Advanced setting in Device Manager for the 2 Channels, I have removed the channels etc. and none of that works. Everything pops back as it was with every boot. I set the second drives on the primary and secondary channels to "none" in the BIOS. No effect. - I tried some registry hacks but they have no effect either. I think most of the published hacks refer to early versions well before service pack 4 for win 2K was released. Basically the hacks just get undone on reboot. I think that if I can re-write part of the INF files (such as mshdc.inf) to enable UDMA, the registry hacks will stay (or be in place when the drivers are written). DOES ANYONE HAVE ANY THOUGHTS ON THIS????????? - I have also tried installing W2k Pro and had exactly the same problem as in WinXP. Quite a while ago I did get the same system running with DMA enabled (all the same hardware) in Win98SE but DVD playback was still a bit jerky (but not as bad as Win2K/XP). So that’s my problem in a large nutshell. Sorry about being wordy. Can anyone get me out of PIO>???????????????????? My tech specs are: Acer Power 4300 PC, 500mHz Intel Celeron, 192 meg ram, Sis 620/5595 motherboard chipset, Seagate st310212a HD, JLMS XJ-HD 166S DVD ROM and as I said earlier; I have tried Win98 and 2000 PRO, and am currently using WinXP PRO. I have onboard audio and video disabled in bios and am using a Nvidia Riva Tnt2 mach 64 pro PCI video card (16meg onboard ram) and a PCI audio card. THANX... the CampMan

See if these help . Problems enabling DMA in XP . http://www.cdrlabs.com/phpBB/viewtopic.php?t=6645 http://www.compguysinc.com/techweb/hardware/dma66.shtml http://www.windowsxpatoz.com/cgi-bin/performance/index.cgi?answer=1036284156&id=1036282433

Jo Thanx for the response. I'll give them a look after dinner and let you know the CampMan

UPDATE ON PROGRESS I have since found a driver for a similar board to mine that has gotten me out of PIO and up to UDMA mode 2 on the hard drive, and up to regular DMA mode 2 on the DVD player. Since I still need to go further on the DVD side I have another question......... What would be the difference between the drivers for the primary and secondary channel versus the driver for the main PCI IDE UDMA controller. Are they the mini port drivers and are they different from the main bus controller driver???? thanx