Asus P5n-E sli FSB wall?
 

so I guess I'll start with system specs:

Core 2 Quad Q6600
2x XFX 8800GT 512mb in SLI
ASUS P5N-E SLI
Crucial Ballistix PC2-6400 2GB 2X1GB DDR2-800 CL4-4-4-12
Corsair 750W PSU

so Basically I cannot get this system to boot at 1200fsb or over for the life of me. I have even tryed underclocking the ram and cpu and cranking the NB voltage and it still wont boot XP at 1200fsb. I even tryed going past 1200fsb to see if it was a fsb hole but no luck either. I have tryed many different bios version including the newest 1301 bios. System is rock solid at stock speeds. I have set memory timings manually too. I honestly cannot think of anything that should be stopping me going over 1200fsb, most other people with this board see healthy overclocks well over 1400fsb. Any ideas? do I have a lemon?

Guess it's rather the CPU then the mainboard.

I even dropped the multiplier on the CPU to underclock it. Seems like the board just doesnt like the fsb. I've never heard of anybody else not being able to break 1200fsb on this board. Seems strange...

Those breaking 1200, was that with dual or quad core.

But indeed, 300/1200 is very low, even for a quad core. Diid you raise pll voltage ?

I have seen many people breaking 1200 with dual and quad cores. But as I was saying, I even underclocked the cpu and ram and raised the fsb (I can run unlinked) and It still would not boot xp. I raised the voltage on everything but it still refused to budge. I also tryed running the cpu/ram linked and with a divider and the system would still not boot at that speed. I'm starting to think I just have a dud here...

Many older nForce boards have big problems with quadcore overclocking. Even more voltage won't help at this point because the chipset is probably at it's end - what does not mean that you can't reach a higher FSB with a dual core CPU.

Which BIOS version do you use?

I have tryed the latest 1301 bios and just about every previous revision. This thing is damn stubborn, I have even had some stability issues at 2.67ghz.

Most users on extremesystems replaced the NB heatsink with an aftermarket product and voltmodded it... though you are really mobo limited here for quad OC'ing and most of them fried their boards running OC'ed quads... board seems to run fine with duallies though

I've given up with this bloody thing. Now I'm not sure whether to swap my quad for a faster dual and try this mobo again or just get another board and Overclock the quad. What board is sli and still a good bang for buck for overclocking? I'd really like another board that allows memory and cpu to be unlinked.

I think 780i is your only option mate... I had a nice board with the EVGA one and with 2 8800GTS 512 in SLI... it had no problem to clock my Quad up to 450FSB and ram at 1200mhz... but any 780i board will set you back 220 euro's

Some have praised 750i FTW from eVGA but opinions are mixed with quads...