RMA CPU from Xander International Ltd. The previous 1008FPMW 555BE has surrendered, it may be caused by extreme overclocking with stock cool and results in unusual blue screen. It’s originally used in ASUS M4A88TD-M EVO, I put it in my previous motherboard ASRock 880GM-LE (using without BSOD for two months) and blue screen for 6 times in 6 hours… So, I decided to take it to the wholesaler for RMA. Luckily, they believed in my words and change for a new one for me immediately. I only wasted 15 mins there and got a new 555BE with code 1046EPM, which had been reported successful unlocking to quad cores very stable and good health. After my testing, it can able to reach 4200Mhz (200×21) on TurboV software overclocked in Windows 7 64 Bit and pass Super PI 1M test in 18.470S at 3800Mhz (200×19). But if you want to run stable in 3600Mhz, it may require up to 1.35V. I can’t test for the stability in 3600Mhz, because the stock cooling can’t cool down the heat produced by the CPU. However, I am able to run it stable with 3200Mhz (200×16) at 1.25V. So far so good!!

Update: It have a strange situation, it will suddenly shut down when reaches 60+ Degree Celsius when running at 3200Mhz (200×16) at 1.25V.

If using higher voltage (up to 1.4V), it will shut down much earlier when reaches 55+ Degree Celsius in any speed, 3.2Ghz or 3.6Ghz also face this situation.

Perhaps the extra unlocked cores are not passing the design limit 62 Degree Celsius and not able to run at high temperature, or it is the motherboard protection from over current.

Update: In early June, I have bought a brand new Zalman CNPS10X Performa. It is quite good and I am now able to overclock to 3800MHz (200×19) @1.425v, it is able to pass prime95 blend test for at least 2hrs (still testing and planned to test for 8-12hrs) and maintain CPU temperature under 55 Degree Celsius (around 52-54). But a core failed at 6hrs prime95 blend test, 1.4375v also failed (the same core, core3 the fourth core).

Perhaps, I need to add more voltage to core3 the forth core, as I have done a wrong setting on it, pushing it to x21 by mistake and added voltage up to 1.45v which cause a little damages on its health.