The last few days...for whatever reason..my screen will go out and either the pc will reboot, or the screen goes out and the vid card fan kicks in 100%.

reseated/cleaned: vid card, ram and cpu and its still doing it.

I think its time for a few vid card perhaps

I've experienced that problem with other ATI cards and it was a PSU issue twice and a card failure once.

sounds like the psu.

Ultra PSU...

well I am online now with the 4670 out of the htpc and I am awaiting a failure.

I will also try the 5850 in the htpc and see if there is a failure.

The psu there is a 500w so its fine for the 5850 very short term.

something should yield a result one way or the other to point at something to blame.

Good call guys.

I unplugged both the 6 pin pic-e , I grabbed two 8pin to 6pin and plugged it into a different rail.

no issues. So I will have to replace this power supply in the foreseeable future.