After long inwestigating i finaly solwed the Hang problem while Gaming with an ASUS M2N-MX, in my case in combination with Athlon64 6000+.
===The broblem is at the Voltage regulators of the motherboard ===
They get to hot and there is no cooling for them and has nothing to do with your CPU or RAM. (As long as the temps are fine of course).
SOLUTION:
Find a Fan that fits between your CPU and your LTP (Printerport) and place it above the Voltage regulators of the motherboard to cool down the Regulators.
I self used Double Sided Ducktape to fasten the Fan on the back of the LTP so it can blow air in to the copper shielded Regulators (these get very hot)
See the Photos how i did it, sinds than my pc does not hang anymore.
For any other questions just ask.
http://img230.imageshack.us/img230/2179/topicfanji7.jpg
Cheers, Fida_Pr