What are considered safe limits on CPU and GPU temps.
CPU = Core 2 X6800
GPU = ATI X1900XTX
Motherboard manual suggests CPU is 140f (60c), current running at 96f under load (Prime95) at 3.3Ghz. Motherboard temp is 102f under load. GPU is 105f (41c) under load.
At what temps should I try to remain under?
P.S. overclocking testing is coming along well in the new dual loop water cooled rig -- full article to follow.
Both temps are fine. X6800 or any cpu should not go past 70c for it's the safe limit. I'm sure thats not really the true barrier but to be on the safe side it should not go over it. As for the gpu, it can operate at much higher temps, but normal stock cooling should run at 50c-60c idle and 65c-75c full load. However gpu can run hotter than that and some can go past 100c and still works.
GPU's have much higher temp tolerances than CPU's. Stick with the book value for the X6800 (as you said 60C), but be very aware that problems are being seen with the temp readings. It 'should' throttle before getting hot enough to damage itself, but don't be surprised if this happens at an odd temp. i.e. way above or below the software declared temp.
The older CPU's could go hotter, XP's were happy up to 80+ according to the spec (maybe 90C I think). My GPU (6600GT) sits at 90-95C underload quite happily, cut out is set at 140C. Not an ATI user so I'm not sure of their limits.