Afternoon all.

I built my first rig 3 months ago.
Spec:
ASUS P5K AiLifestyle Series iP35 Socket 775 eSATA 8channel Audio ATX Motherboard,
Core 2 Duo E6750, Corsair 550W, Centurion 5 w/ side window, Xpertvision 8800GT, 4GB OCZ 1066MHz RAM, 250GB WD Caviar 16MB Cache, 250 GB Seagate 7200, 80 GB Seagate 7200, 320GB USB Seagate HDD, 2x DVDR, Logitech G5 Mouse, Saitek Eclipse II Keyboard, Samsung Syncmaster 20".

It has been randomly rebooting since yesterday with 2-20 minute intervals. The reboots have occurred in Windows Vista x64, Ubuntu Gutsy Gibbon x32 and in BIOS and memtest. I have tried swapping my RAM out for 1 stick of my old ram, have tried different slots.

Have tried using an old PCI video card, no luck. All fans seem to running fine.
I have been monitoring temps and voltages in BIOS and have managed to goet some numbers before it rebooted on me:

CPU temp: 34 degrees C
MB temp: 42 degrees C
VCORE voltage: 1.304v
3.3V: 3.312V
5V: 5.112V
12V: 12.152V

Is it worth trying flashing the BIOS? Anyone got any suggestions. All parts are 3 months to 1 month new.

Thanks.

If it only started a day ago (been fine for 3 months) - something is failing when components reach thermal stability - probably memory.

Thanks for the reply, i have tried swapping the memory out and it still seems to occur, same with swapping out the graphics card. You think it could be the CPU, its showing low temps atm 23 degrees C in PC probe II ATM, i did fit a new better CPU fan about 3 weeks ago for it.

Well. Aslong as you followed instructions that came with new CPU fan. Secure etc. Run something like Orthos/Prime95/superpi to stress cpu! It might even be the motherboard chipset...

It seems to take about the same time to reboot eitherway. Ive had it reboot in BIOS after 10 mins but just managed to get 15 mins on Medieval II: Total war on max settings. Ill try it though. Theres really just no way to tell whats shutting the system down though is there? No beep codes or memory dumps or anything. Dunno what to replace or RMA. Its likely PC will reboot before end of stress test. DO you think flashing BIOS would be of any worth. It seems like something broke though because its been exactly the same since that one moment where it first rebooted itself.

Can do (make sure to save a copy of old BIOS - to floppy), incase things go pear shaped...

Alright ill try that too, running Prime 95 ATM and monitoring CPU temp which asus pc probe II reports at 34 degrees C which is pretty good. Thanks for the help so far Wazza.

Hi BlueYoshi,
I had exactly the same problem with my setup.
I also had P5K, E6750, and Corsair VX550W.

It ran fine for about 3 months, then one day suddenly it started rebooting.
One of my memory was faulty, so switched with a new one. It ran fine for nearly a day, then the prob started again.

I thought it was some sort of a heat problem because it usually restarts after running for a while, then once it restarts, it would restart every five minutes or so, whether it be in BIOS or Windows or memtest.

I looked at Asus forum, and seems to be a fairly common problem with P5K series. The store I bought it from was kind enough to take it back and switched to P5K Premium. It's been running fine since.

you can try flashing BIOS, but I think you might have to RMA it.

One other thing, your temp reported may not be accurate. On my system, SpeedFan reports CPU temp as 15 degrees less than its actual value. Coretemp seems to display the correct temp. Your CPU temp should be near 50 to 60 degrees at max load with Prime 95.

Good luck!

Thanks so much for your reply kvnpark, its reassuring to know somone else has the same, problem. I think my RAMs fine cos I swapped it out, ill have a gander on the ASUS forums. If the BIOS was corrupt i wouldnt be able to POST so unless theyve fixed it RMA will be the way. I looked at temps in BIOS and Asus PC Probe II, how do i find the real temp, lol. I dont see any reason why my CPU would be overheating now though. Thanks for the advice.

yeah, usually random reboots are from the mobo. I've had a lot of old crap basic Dell rigs where they're cheap proprietary mobos reboot randomly. I'm glad it's not the VX550W that is the problem, because I'm just about to get one .

Don't worry Dave, I've just tested the PSU in another system and have confirmed the mobo is where the problem lies. Its good being able to rely on a good powersupply. At least when your system fails you dont eye the VX550W suspiciously. Thanks for your advice guys.

I had the same problem last year with a P5K Deluxe. I ended up returning the board and got a Gigabyte instead.

Funny thing is, MicroCenter just had a sale on a P5K (non-deluxe), so I picked one up a few days ago (second time, shame on me)...this is for a second rig, btw...and the thing can't even POST. I still suspect it being something to do with the board itself, or memory compatibility.

All of the components I have in my current rig were on the P5K Deluxe I got last year, and after switching boards, I've had no problems for over 6 months now. So, at least I know none of my other parts were bad. Seems that this problem occurs only on the P5K & P5K Deluxe, and not the P5K Premium.

You're welcome BlueYoshi.

Hopefully it all works out for you. It is weird that, in both of out cases, the problem started after 3 months

As for temp, I'm pretty sure CoreTemp gives the correct temps.
Both PC Probe and SpeedFan reports 15 degrees lower from my experience with both P5K and P5K premium.

Also, Premium also has this problem from what I see on Asus forum. Hopefully mine stays prob-free.