After struggling for quite awhile with heat problems I finally decided to take the heatsink off and investigate. After reading many posts about low temps using the stock fan I realized that it wasn't a fan problem, and that the stock fan would work just fine. That could only mean that the connection between the heatsink and the processer was bad. The fan was cooling the heatsink but the chilling affect was not making it to the processer.
After removing the heatsink I didn't see anything out of the ordinary. I cleaned the two surfaces like Artic Silver suggested and applied a new coating of thermal compound thin and smooth as recommended and put everything back together. Reinstalled the card, booted up the PC and right away I'm seeing temps starting at 50c and then climb to 104c playing Battlefield 1942 and then it locks up. I took the card out again and removed the heatsink and this is when I found the problem. Only about 10% of the heatsink was making contact with the processer! The thermal compound told me everything I needed to know in a heartbeat. Man was I pissed and releaved at the same time, and that ain't easy to do!
So, all this time when we thought that ATI was putting too much TC on these boards it was intentional, they were actually doing it to cover up a bad design. Is "cover up" too strong a language? How about "work around", does that sound better? Well anyway, I recleaned the surface and applied a liberal amount of TC, enough that would fill in the gap. Reinstalled the heatsink and card and fired up the PC. Unbelievable results!!!!!!! My idle temps as I write this today at 4:30am is 32c and max load temp is 59c playing FarCry on VeryHigh settings and before I could barely get FC started before it locked up.
Conclusion: For all of you guys/gals having heat issues with your Radeon X850XT PE if you do what I did you will be amazed. With temps like this I doubt I even need to consider replacing the heatsink with a Artic Cooler, leave well enough alone.
Happy gaming.
Tepabajo
