Ok, i just received my new 7750 and its doing the samething. runs in prime95 for about 25 minutes then one core fails out. Im not sure whats going on. Ive ran memtest86+ plus for 7 hours with no errors. Im running G SKILL 2x 2gb at 5-5-5-15 at 2.1 volts, 1066 mhz. im running the cpu at stock speeds and 1.325 volts.
Also, my temps are topping out at 55c with stock cooler. im running the large fft test.