Hello all. I am experiencing system instability during playing games or during some other high-cpu usage. My specs are: AMD AthlonXP 2500+ (11x166MHz) EPOX 8RDA3+ nForce2 2x256 Mb GEIL Value PC3200 @ 166 MHz 2.0-4-4-7 (CL-RCD-RP-RAS) Sapphire ATI Radeon 9550 128MB (250MHz,400MHz) 1xHitachi 80GB SATA 1x DVD/CDRW combo PSU AOpen 300W Windows XP Pro SP2 Thing is, when I downclock FSB everything is stable and no problems occur. I decided to test stability with Prime 95 and this were the results: Test 1: Small FFTs (max FPU stress, RAM not tested much) Test 2: In-place large FFTs(maximum heat,power consumption, some RAM tested) Test 3: Blend (tests some of everything, lots of RAM tested) 1) CPU @11x100Mhz RAM @100Mhz All tests run continuously for several hours, no problems 2) CPU @11x133Mhz RAM @133Mhz Same. All tests run continuously for several hours, no problems 3) CPU @11x166Mhz(nominal clock) RAM @166Mhz Test 1: Everything ok for several hours, stable Tests 2&3 : After 15-40min system freezes 3) CPU @10x200Mhz (overclocked) RAM @200Mhz Test 1: Everything ok for several hours, stable !!!!! Tests 2&3 : After 15-40min system freezes I used Motherboard monitor to sensor temps and voltages Temps are within normal (max. 51-52'C on full load) Voltages within normal (+-5%) I tested RAM with Memtest86 overnight and no errors reported. Im asking you, what could be the problem here? Faulty MoBo, more PSU power needed(not many components, should be enough), ram incompatible with mobo? What is your best guess? Help!