Asus P5Q Deluxe possibly broken? Won't P.O.S.T occasionally

[psolord]

Hey guys.

I have a system with the following specs.

Asus P5Q Deluxe (P45 chipset)
Intel Q9550 E0
OCZ Platinum 2X2 DDR2
Nexus Silent Modular 850W
ATI 5850 Crossfire

Lately it is manifesting the following strange behavior.

If it is switched off from the power supply for some time, it won't post. The same happens if I keep it plugged in but turned off for a week or so. It will power up, but won't post.

I have to reset the BIOS for it to post again and then it gives me an overclocking failed message and wants me to enter the BIOS and set things straight.

The funny thing is that this happens whether the system had overclocked settings or stock settings.

If I set it to say 4GHz and quickly power off and on again, it works like a champ. Never complains, never crashes. If I try the next day without pulling the plug or switching off the PSU, it may work again with no problem.

So in a nutshell, the problem manifests after a lengthy period of complete absence of power.

Things I checked:

- The cmos battery. It works Ok since the time is not lost
- Tried both 5850s one by one in case one was broken. The problem still exists and both cards work fine anyway. No graphic glitches and still perform admirably in CFX mode
- Switched PSUs with my second PC.
- Did a 12hour memtest with everything reported ok.
- Temperatures are fine when it works

Do you guys have any idea of what could be causing all this. My eyes are turned to the motherboard but I don't know if it could be the cpu or anything else for that matter.

I also thought I may be looking at some transistor degradation, since the system was working at 4Ghz since I got it, but not 24/7. So I tried relaxed/stock timings and settings, but with increased voltages all around, but still this did not help.

Any help will be greatly appreciated.

 

[Ketchup]

You said you checked the CMOS battery but have you replaced it?

Try running RAM sticks one at a time.

 

[psolord]

Won't hurt trying. Thanks.

 

[psolord]

Well the weirdness continues. Installed new battery and tried with single memory sticks. The system still does not p.o.s.t after a long period without power.

Now here is where the fun part starts.

At exactly the time I installed the new battery it seemed to work fine for a while. Probably because the BIOS had been reset due to the absence of the battery.

I started doing some testing but when I tried Sniper Elite III with crossfire enabled, I saw many artifacts. The system hanged after a while. I rebooted and went to test again. Same thing. It also artifacted in Wolfenstein, although this does not support crossfire, so I guessed there was something wrong with my primary card. After that, the system was hanging right after booting windows giving me a white screen and after that it did not post again.

In any case, just to be sure, I took out the cards and installed them on my primary system which has two 7950s. I installed the 7950s on the problematic rig. Did not touch a thing regarding software.

Wanna guess what happened? Both systems work great! I have no artifacts on my 5850s and the problematic rig is not problematic any more. I have made quite a few complete power cycles and it starts up like a champ every time. I did many hours of testing with gaming load, just to be sure that the problem does not manifest after it has been heated up.

I haven't seen weird stuff like that, since my 486 days, lol.

What do you guys make of it? Should I call Ghostbusters or something?

The only thing I can guess is that either the chipset is about to get shot and plays games with me, or there was some bad connection in the PCIe slot with my 5850s or some dirt or I don't know what, although I flipped the 5850s around more than once, in my previous tests.

 

[VirtualLarry]

Do the 7950 cards take less power than the 5850 cards? If so, I would investigate the PSU.

 

[denis280]

Do the 7950 cards take less power than the 5850 cards? If so, I would investigate the PSU.

Bingo

 

[Ketchup]

Do the 7950 cards take less power than the 5850 cards? If so, I would investigate the PSU.

Or a bad pci-express slot.

 

[psolord]

Do the 7950 cards take less power than the 5850 cards? If so, I would investigate the PSU.

According to TPU the 7950s draw more power.
http://www.techpowerup.com/reviews/MSI/HD_7950_Twin_Frozr_III/24.html

The 7950s of this review, only run at 880Mhz and mine run at 1Ghz/1.25V (Gigabytes Windforce V2).

Also as I said in the first post, I installed the psu from my secondary pc to the problematic pc but the problem remained. Moreover the psu from the problematic pc went to the secondary pc and that system continued to work fine and it has two fermis and a lynnfield at 4Ghz.

edit
for the record

rig1 psu Coolermaster Silent Pro 1000w
rig2 psu Enermax Galaxy 850W (now installed on rig 3)
rig3 psu Nexus Silent modular 850W (now installed on rig 2)

 

[psolord]

Or a bad pci-express slot.

This is what I fear the most, but still, my 7950s run fine on the problematic pc. Played an hour of Sniper elite 3, with crossfire enabled with no problems. Only the gpu usage was around 40-55%.

I will throw in some 3dmark runs tomorrow.

I also played an hour of Sniper Elite 3 on the 5850s as well and all went well with them as well.

So to sum it up

Q9550+P45+5850 cfx post problem
I5 2500k+P67+5850 cfx OK
Q9550+P45+7950 cfx OK

I forgot to specify that the problematic rig, has been running with this configuration since 2008-2009. It just started misbehaving now that I was planning to sell it. And they say PCs are soulless machines! Heh!