Howzit fellers,

I'm hoping that someone could shed some light on the dim depths of my OC problem. Here's system specs:

Asus P5Q Vanilla rev1.3
Q6600 SLACR G0
2x1GB Kingmax DDR2-1066 5-5-5-15 (which OC's very nicely to over 1200-odd MHz)
Asus Arctic Circle HSf
MSI HD4850 512Mb
550W PSU
Currently running Ket's mBios 1406
Windows XP 32-bit SP3 freshly installed, latest drivers, etc.
Superchannel case with excellent cable management and airflow (if I may say so myself)

My problem is that I am unable to get a FSB speed anything higher than 400MHz on my P5Q. I can run 399 just fine, the moment I set it to 400 or anything above, the board refused to post or recover from the setting. I have to hard reset the BIOS to get her up and running again.

It certainly sounds like it's a FSB strap problem, but regardless of the strap that I force it to, the problem persists. There might also be another clue - regardless of FSB, the moment I set the strap to 400MHZ, the problem rears its head even at low FSB.

I've played with NB voltages, tried Ket's mBIOSes, played with GTL and PLL voltages, I've tried pretty much everything, including swopping the ram for other Kingston sticks and swopping the Radeon for a PCI S3 Virge.

No go. Even at the lowest CPU multiplier.

It's not a ram problem (I think), I've underclocked the mem frequency also to see if it goes away... it doesn't. I've added extra volts to the RAM, no go.

The board is extremely stable at 399, I just set everything to auto, turn down the CPU voltage a notch or two (it autos at 1.44v@~3.6GHz), turn up the ram voltage a notch or two, and away she goes.

The Arctic Circle does a very nice job of keeping things cool, I think I've got a good Q6600 as it hovers around 64'C at full prime load at 3.6GHz. I know it can do better, but ideally I'd like to crank the FSB and lower the multiplier.

It's somewhat disappointing to read about guys with P5Q's who are doing 425, 450 or even pushing 500Mhz FSB out of the P5Q. One thing I will say is that the passive NB cooler, while beautiful, isn't up to the job and it gets freakin' hot. I've added a small fan to it and that certainly helps, but it doesn't solve the problem.

I've read that the P45 and quads don't talk together so well on some boards, and that Quad + high FSB also often doesn't work. Is this true? Also, is it possible that my Quad has an FSB wall of incidentally 400Mhz?

What are the symptoms of hitting the FSB wall? Surely it should at least POST even if it's not stable?

Preeze help, pretty preeze sugar on top! I am very happy with the 3.6GHz that 399FSB gives me... but I know it can do better. I wouldn't be here at this fine establishment if it didn't matter, no?


Thanks!
Riaan aka Level 88