It's a HKC USP 5580. The specs can be read on a sticker that's on the psu, posted a photograph on http://www.happypanda.nl/psu.jpg. It says 30A on the rails I guess. Only PSU I have for testing purposes is my old one, a 400W with 8 and 14 A on the 12V rails, so I think that PSU wouldn't be of any use, would it?
Thanks again for the reply, it's much appreciated!
Edit: I just reinstalled drivers (9.7 beta again) and the game seems to be running fine (played for half an hour / 45 minutes or so)... tomorrow wil probably be the moment of truth as I'll be cooping the best part of the day :) I'll let you know.
Edit2: Got the same artifacts within a few minutes, when playing this morning... so should be either my video card or my psu I guess, as nobody else seems to be having these problems.
Edit3: Get the artifacts in Furmark and AtiTool Artifacts test too now, so THIS problem is NOT a problem in Arma2. Thanks for all the help, I'll be contacting the shop I bought the parts from.