CUBASE 6.5 CPU Completely stumped power user

Hello, been using cubase and nuendo for about 7 years andbuilding pcs for it, never posted on a forum before but this on is a doozy.

Just finished a new install of Cubase 6.5 on a fresh install of Windows 7.
Core 2 Quad 2.4, 4 gigs of ram RME UFX etc. Its a machine Ive used without incident for several years.

Cubase is experiencing massive CPU spikes, even with very simple play back of a single stereo WAV. Its like everything is CPU times ten. I can just play a WAV if I crank the Buffer on the RME to Max. Keep in mind I have been using this with the same software and hardware on an earlier install for years. no probs.

For what its worth, Protools functions perfectly on the same drive.

The weird part, I can go back to the old drive and boot up from it and everything works fine. exact same hardware.

I have tried everything to replicate the other drive, it was at a slightly earlier version of Cubase and Windows. also it was installed as Cubase 32bit on a 64 bit windows install.

So Ive tried:
Moving my new install to a different drive.
Uninstalling protools
going to the same slightly earlier RME UFX driver
Using the UFX as USB instead of Firewire
reinstalling Windows to an earlier non updated version
a complete reinstall from scratch without updates of windows 7 and an install of nothing but RME drivers and a raw new install of Cubase 6.0 on a new hardrive. SAME THING
Ive tried a hundred different CUBASE settings and hardwrare settings, again no change. It only works on the old install from last year.

a few other things too, Im probably forgetting. Ive been trouble shooting for DAYS

Teh only thing different about the old drive from the new drives, installed with IDE Bios instead of ANCI Bios. I might try that next. but it seems kind of silly, also the new drive i want to use is an SSD. So I really should install with ANCI

So anyone got any ideas?

Sounds like DPC latency. Bios versions definitely affect this.

this link may help

http://www.gearslutz.com/board/music-computers/365525-what-dpc-latency.html