Faulty motherboard?

[Seanrb]

Following on from my thread about having problems with downgrading the BIOS on my P5K i want your opinion on a few things that have happened lately.

Basically, i started off with the 0902 bios and had my Q6600 clocked at 3.4ghz stable (12 hours prime, no errors or warnings). I then upgraded to the 1009 (?) BIOS and couldn't get it stable even at 3.2ghz. So i eventually managed to downgrade to 0902 again, i have now got my Q6600 stable at 3.2ghz (14 hours in prime, no errors or warnnings) but it won't last past 1 minute in Everest no matter how many volts i put through it if i go any higher. Aswell as this i have had a couple of other things happen.

1) Every so often i get the "Overclock failed" screen with i boot the computer, but it if i restart it willl boot fine (remember, 14 hours in prime, no errors or warnings) and run fine.

2) A couple of days ago i turned the computer on, it go to the full screen logo screen, went blank as it does when it switches to the next screen, then restarted and carried on doing this in a loop until i turned it off.

Is it worth me taking the mobo out and RMA'ing it, or has changing the BIOS just lowered the clocking capablities of it?

Other components are:

Q6600

4GB Crucial Balistix Tacer 1066mhz

Seagate Barracuda 7200.11 250GB

HIS Radeon 3870X2

The Q6600 is watercooled and loads temps are ~49C.

 

[Toxcity]

Tried upping the NB voltage and disabling spread?

 

[Seanrb]

Yeah, none of the available settings for NB voltage make a difference.

I've just thought of something i completely over looked.

When i had it at 3.4ghz originally i was running a 3870 and air cooling, I'm now running a 3870X2 and watercooling, PSU hasn't changed which is an OCZ gamexstream 600W, could this be a problem?

According to the eXtreme power supply calculator my current setup draws 392W stock and 485W clocked at 3.4ghz.

Where as my old setup drew 319W stock and 406W clocked at 3.4ghz.

Am i right in thinking that an 83% load efficiency on a 600W PSU means you are safe loading it upto 83% of the rated value? If so then i am pretty much hitting the limt.

 

[Toxcity]

I am pretty sure that the 83% load efficiency is stating that when under load only 17% power is wasted/leaked.

Powersupply could be an issue but I very much doubt it, I have a 620watt running a 9800GX2, water kit and an overclocked quad.

 

[Seanrb]

Hmmm. Think i will try my 7300GS & less RAM tonight to rule out a power shortage.

I think i will contact Asus in the mean time as well, see what they say about what has happened recently.