Torvald, what resolution and texture settings are you using?
Also i think that some background tasks bog the system down, be it antivirus, firewall, malware, spyware, internet explorer, skype, instant messanger or whatever.
I have no framerate problem with trees and my system is way slower.
I have no idea which program it is but i could imagine some messaging, fw, antivirus or maybe some kind of winxp help, indexing, sceduling, update whatever program runs in background and seriously breaks the system.
For example some networking program might have to examine every udp package needing cpu power when ah is transfering information?
As i see it most of you say it ran great when trying with the new system and a few days later it doesnt run any good, something changed in the system meanwhile and that is the problem.
For example using outlook express opens up the instant messanger and that one stays in background all the time.
Windos trys indexing filesystems for fast search, maybe it tries to index the ah2 files because they get touched all the time it indexes them constantly while playing?
Antivirus with constant file check checks every file opend and bogs down the comp?
Omega drivers wont help in this case, as fast as they might be they only buy some frames if at all, as i understand is you have a quarter of the performance that you expect.
Maybe skuzzy has an idea how to debug the problem... maybe dump a thread list into a txt file with a hotkey? As soon as you jump out of ah2 the effect that is the problem will cease... so maybe you can put in a debug switch into ah and pull the info somewhere?
Can ah2 check how much cpu time it gets and how much cpu time is for system and other tasks? Those 3 values alone could give a hint if its real a ah2 problem or another task running, as i suspect it is?
Sorry if i sound to critical but i find it verry strange that it runs perfect on new installed system and 5 days later its bogged down.
You installed winxp sp2 between first ah2 test and the slow problems? Switched off all the stuff coming with sp2, like firewall, online update, office quick launch and others?