I have some time in my hand last weekend and manage to find the source of problem and the solution for my p35 lt board that keep OFF and ON rapidly when being clocked high. To bad taking picture doesnt come to my mind until I solved this problem.
> The culprit is the Mosfet heatsink itself which have a bad dimension at the screw mounting area.
> This part of the mosfet which I boxed in red line have higher dimension thus resulting a very bad contact with the mosfet and 3 of the FET even barely touch the ramsink.
> At first CN suggested that the backplate causing the mobo to warp but after removing it and using default mounting kit the problem still there. After a little bit a tought ; the backplate is there to prevent warping in the first place.
> I give a shot by removing the Mosfet heatsink and find out that there a chunk of TIM on every FET there that put to much and badly applied. I guess somebody have a lazy day there. China mobo Rev. AA0
> After cleaning the area and the heatsink with cotton bud , tissue and aceton I reapply the TIM on the every FET and put it back to see how the contact. To my suprise 3 of the FET near PS/2 barely spread the TIM which show a near no contact with the heatsink. The other 5 FET make quite a square spread with the TIM altough not perfect enough for me. I reapply the TIM 2 times to make sure.
> So I sand down those part quite a lot which I boxed in red to make it sit lower with the mobo thus resulting both of them make a perfect contact. I retest by reapplying the TIM and got all perfect square spread on all 8 Mosfet.
> Soo at last the mobo doesnt OFF and ON rapidly and instantly anymore everytime I start the prime95 with higher clocked about 3.9 Ghz instead of normal restart which sign of normal instabilities. Need more time to tweak.
This all leave me with a mess and lot of time troubleshooting because I havent test the mobo before finish it up with my loops. I am not happy with the time I lost troubleshooting and the the pcie layout. I will sold this mobo back and and get x38 or P45 if they come out and have better pcie layout.
The Culprit
MESS
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