Yes I hear the sounds too after it hangs. However, the sound does hang eventually as well, once the directx buffer is run out.
69C is still cold, and should not cause a crash - however, there is a particular voltage required for stable operation at 69C and your chosen clock speed.
I have found that for 2D operations, the card will keep running up to 115C at which it will throttle back (pause) and resume operation at 113C.
This overheat behavior has not been seen yet for 3D operation, as it will hang up before it gets that hot when clocks are above 796Mhz.
The speed is a factor of 13.5Mhz increments - half of the clock crystal frequency of 27Mhz.
So your reported speed choices are 796, 810, 823, 836, 849, etc. This is by design.
Originally Posted by TRWOV
Apparently it's some sort of overheat protection as just the GPU locks up (but doesn't crash) and I can still hear the game sounds. I tested with the 3dmark06 demo and it also locks up but the sounds keep playing as normal. I've tested at 810Mhz and haven't got any problems. With 3d06 demo running I get 69C. The fan never goes above 56% for some reason.
Odd thing, I can't set the GPU at anything over 810 until I hit 824. For example, if I set it at 820 GPUZ and CCC report 810. Once I set it at 824 it goes to 824.
For 2D and video acceleration it can do 860 but once a 3D application starts it crashes immediately. Maybe it needs more voltage but I haven't changed it, it's not my thing but I guess I'll give it a go just to see if anything changes. I'll report later tonight.