Maxtor hd & udma

[tholts]

I replaced 2 WD 5.1 gig drives with 1 Maxtor 13.6 gig. All 3 drives operate in UDMA2. When I check the DMA box in device manager, the system will boot until the icons are supposed to apper on the desktop, and then it hangs. Upon reboot, win98 reverts to an earlier version of the registry and then boots normally.
System: Asus p2b bios 1.006, p2-400(@448), 128mb PC100. Primary ide channel = Maxtor 13.6 hdd master w/jumpers properly set, Acer 18x cd rom slave w/ jumpers properly set. Secondary channel = Sony Spressa cd burner master, internal atapi zip slave, all jumpers ok. Problem occurs with Acer cd rom connected
and disconnected. Bios set to auto-detect UDMA. The Intel 82371AB/EB PCI Bus Master IDE Contoller is present alongside the primary and secondary IDE controllers. The Adaptec threadmark test gives a data transfer rate of 3.99 MB/sec, with an average CPU utilization of 65.43%, both of which seem poor for UDMA2 performance (test was done with Acer cd rom removed from the primary IDE channel).
Question: does the DMA box need to be checked for the drive to operate in UDMA2 mode, or does it simply operate in that mode automatically?
Any ideas?
Thanks in advance, all you bus-master drivers.

[tholts]

Still working on it. I tried going into bios & resetting the UDMA manually to 4/2; I re-ran Threadmark & got 4.10MB/s and CPU utilization of 66.35, essentially the same performance. I uninstalled Norton Antivirus & the boot sequence got to the Startup sound, the taskbar appeared and the icons flickered briefly; then I was at the desktop again with a non-functioning pointer. ???

[BF]

Your DMA is not enabled, or your cpu utilization would be closer to 25% under ThreadMark 2.0 for that drive. Also, your transfer rate under ThreadMark should be higher. You do need to check the DMA box to enable it. Are you sure you don't have the Intel BM drivers installed (you shouldn't)? I would suggest posting your inquiry on the message board at [url]http://www.bmdrivers.com/[\url].

BF

[BF]

Sorry, messed up the url. Should be:

http://www.bmdrivers.com/

[tholts]

It turned out to be an overclocking issue. I baced down from 112x4 to 100x4 and all is well. Thanks BF for offering some insight to the problem; DMA and UDMA are not the same thing after all.