Just incase you didn't see my last post with Vista and I have no clue if you've tried Vista with X850's or not (Obi, I know you have X1900 XXXXX series), I'd be real leary about installing the beta drivers that ATI put out with Vista. Just letting you guys know, I'm replacing two out of the four that I bought because of it (one went to a friend and the other was supposed to be sold on ebay- didn't happen).

well got 4 ATi based rigs here with the following cards

ATi Mobillity Radeon 7500 32MB DDR 128Bit it runs with XP Pro + Omega Catalyst 6.03
Ati Mobillity Radeon 9800 256MB GDDR2 256Bit it also runs with XP Pro + Omega 6.03

Ati Radeon 9550 256MB DDR1 128Bit with XP Pro + Omega Catalyst 6.03
Ati Radeon X1900 XTX 512MB GDDR3 256Bit with XP Pro + Omega Catalyst 6.07 + ATi Tray Tool which was with that driver, as experiment

I must say that Vista has too many childhood deseases and I recommend you to wait til Service Pack 2 or at least Service Pack 1 arrives, so that the most troubles have been removed.

I would say stick to Windows 2K pro + SP4 or Windows XP Pro + SP2, they are older, much stabler and safer to toy around with, and upto date enough for the upcomming games.

As my experience with ATi cards I always snatch the Omega drivers, since they have far better imagequallity that the original ATi ones and they are better for ingame performance, where 3D mark they are a bit slower but that program has no issue what so ever, in my words not important since I buy GFX cards to play with and not bench.

the MR7500 aka ATi M7, MR 9800 aka ATi M18 and RV350 aka ATi 9550 have all the same Omega Catalyst driver + Radlinker with RadClocker.

For all Ati cards X850 series and below do the following:

Remove the old driver first, then reboot.
Then Install the omega driver 6.03 and NO ATi Tray Tool!!!
for Windows 2000 Pro + SP4:
http://www.treiberupdate.de/treiber-download/z-dltreiber/download_treiber_999c.p...

For Windows XP Pro + SP2:
http://www.treiberupdate.de/treiber-download/z-dltreiber/download_treiber_999c.p...

Here is the great tune tool, it's really gorgeous too whoo hoo!
RadClocker:
http://users.adelphia.net/~webspace/RadClocker2030.zip

Rad Linker:
http://users.adelphia.net/~webspace/RadLinker2033.zip

RadLinker for WinXP64:
http://users.adelphia.net/~webspace/RadLinker642035Test.zip

no Vista here 2K Pro & XP Pro all the way Not in to Beta stuff that does the job only halfway.

But what chipset do you have then, if it's the RD580 with ULi M1575 South Bridge, like my ASUS A8R32 MVP Deluxe has, that chipset needs no driver it just works, there isn't even a driver bundeled with that chipset , it's totally unified architechture, it just take's on what it comes acros, just like how the AWE64 Gold soundblasters used to work, plug in and Rock 'n' Roll.

If you have the older RD480 chipset with the SB450 southbridge that may cause instabillity problems, it's because of the SB 450 southbridge chip that chipset does relly on a driver, RD580 + ULi M1575 does not