I'm going to be working under Windows XP Pro for a couple days just to see how 'different' things are now from what it was a couple of months ago. One thing I can already say is that I got a little improvement in this Benchmark on the first run. This is with the same 8.4 drivers for XP for my HD3870 and 'trying' to use the same settings as what I was using under Vista. I say "trying" because, when I attempt to use ATI Tool to make the adjustments, it reboots my PC. It's also consistent because I've tried three different times to make adjustments and three times the PC rebooted.
So, I used ATI CCC to increase my GPU Clock to 840....which is the highest CCC will allow. And, for some reason, CCC locks down the memory to 1170. I was at least able to get the Memory increased with ATI Tool under Vista. However, with just the Clock increase to 840, there is an increase in the results for 3DMark 06 by about 300 Marks.....to 11455.
http://service.futuremark.com/compare?3dm06=6777977
I'm wondering why ATI Tool is causing the reboot under XP Pro whereas there was no problem with it under Vista. ???