My system has begun to digitally distort when running projects in cubase 6. I did not install any new HW or software. It occurs at all buffer sizes and , although it can happen at any time, it's most likely to occur when I open a project or revert to a saved version. I also get a dropout in cubase playback when I insert a cd (with audio) into the cd drive.

The vst performance meter shows that I have plenty of headroom. I'm using ASIO Fireface as my ASIO driver. I was able to get rid of distortion by disabling and re-enabling my UAD-1 cards so I though they might have gone bad. I disabled them in Device manager and still have the problem. I have not had the problem in Wavelab but am only playing back stereo files in it. I have tweaked every Fireface setting as well as VST settings in Cubase prefs. I've tried installing newest RME drivers and updating cubase 6. I'm running each Fireface independently to my firewire 800 card via FW 800 cables of same length and make. Sometimes it will run flawlessly (still has dropout when cd inserted which is probably unrelated) all day and acts-up the next. I recently imported 2 audio cd tracks into an empty cubase project w/ no plug-ins and had the issue right away.

Cubase 6.0.7 (32 bit)
Fireface up-to-date on firmware and drivers
Windows 7 Home Premium 64 bit OS
Processor: Intel Core i7 CPU 870@2.93 GHZ
8 GB Ram