I have just purchased a 160Gb Seagate Barracuda 7200.7
drive to use as my new boot drive. On installing Windows
XP, the drive works perfectly, and Device Manager shows the
transfer mode for device 1 on my primary IDE channel (the
Barracuda drive) as Ultra DMA Mode 5. Every time, however,
that I install Service Pack 1 for Windows XP, the transfer
mode switches to PIO, and performance is awful. I have
tried installing Windows and then the Service Pack at least
4 times now, and the same thing happens every time. How do
I re-enable UDMA 5 under Service Pack 1? (Selecting 'Use
DMA if available has no effect - it still stays on PIO)

Thank you very much for your time.
.

IDE drivers fall back to lower transfer modes when they detect errors.

Try installing the manufacturers drivers for you motherboard VIA 4in1 4.43 in your case i assume.

And double check that you haven't disabled the DMA mode in BIOS.

Just had the exact same problem - check your BIOS settings.

I did the fatal mistake, yes I am asamed :blush: , to first ignore this. And after X hours went there and of course... wrong config in the BIOS.

Check them before anything else, and if you have - just check again .

It turns out that my drive was faulty, and since I haven't received the replacement yet I don't know if the same thing's going to happen again. My BIOS settings were all correct (I have an ASUS board with ALi chipset) and what is strangest is that my current HDD (the one I want to replace) works perfectly with UDMA 5 (it's actually a faster drive than the new one too - Ultra ATA 133 rather than Ultra ATA 100 for the Seagate). That's why I was so puzzled. I'm going to have to wait now for the replacement to see if I still have this problem.

Just to be sure... you have check both primary and secondary channel as well as both devices on each. I missed this first time around - don't asume if you're not 200% sure.

Not any mistrust - just making sure, you know...

Primary IDE channel only has the hard drive on it (and it is an 80 conductor, 40 pin cable, as required for UATA 100). Secondary channel has DVD-ROM drive and CD-RW drive on it, both running at UDMA 2, and both working perfectly. My current HDD is a Maxtor Fireball 3, and is capable of UDMA Mode 6 (which its set to in the BIOS, but Windows always shows as UDMA Mode 5). This drive has always been working fine. Therefore the obvious conclusion would be that it's a hardware problem, but it only happens after installing SP1, which suggests software. You can understand why I'm so perplexed.