Hi guys,

i’ve recently taken delivery of a new custom pc.

The specs are:
case: lian li 2100
cooling: water-cooling of cpu, gpu and northbridge
cpu: quadcore intel core 2 extreme qx9650 – overclocked to 3866 mhz (11 x 351)
m/board: asus p5k premium/wifi-ap (black pearl edition)
chipset: intel bearlake p35
psu: hiper hpu-4m880 (880watts)
ram: 2gb crucial ballistix 1066mhz ddr2 ram (reported as: 2 x 1 gb ddr2-800 ddr2 sdram (5-5-5-18 @ 400 mhz) (4-5-5-15 @ 333 mhz)
gfx: bfg overclocked nvidia geforce 768mb 8800gtx
hdd: x2 wd raptor 150gb sata in a raid0 configuration
sound: creative sb x-fi xtreme audio sound card
os: windows vista home premium
bios: version 0404 (american megatrends)

i’ve had one or two problems with the computer but most notably i had an issue with the cpu apparently overheating.

I turned on the computer first thing in the morning (so it had been off all night) and i’d barely logged into windows when it just shut down without warning. I tried again and it happened before i got as far as windows so i rebooted and quickly went into the bios to see what the hardware monitor was telling me. It showed the cpu temperature as 100ºc which was rather alarming! i presume it would’ve gone higher but was limited to 100 degrees (?)

i removed the sides of the case and had a look inside – not sure what i was hoping to find really but it seemed the sensible thing to do. Anyway, after having a look around and giving a general prod of this and that (tell me if i’m getting too technical for you) i decided to boot it up again to see what would happen this time. It then started up fine with the cpu temperature in the high 20s/low 30s. Very odd. It was fine for most of the day and then it did it again about 8 hours later.

That was over a day ago and hasn’t re-occurred since but i’m still pretty worried about it. I’ve invested in various temperature monitoring tools, namely everest ultimate, sensorsview and coretemp as i’m paranoid it’ll fry. I’ve run a couple of stress tests and the maximum cpu temperature was a little under 65ºc. I’ve set the alarm threshold at 65 within sensorsview as i want to shut things down before they get really hot.

A few days ago i changed over the supplied psu to the one referred to above as the original one was making an annoying high-pitched buzzing sound which was going through my head and driving me nuts! i’d never changed a psu before – the limit of my experience is upgrading/installing ram, graphics cards, sound cards etc… so my first concern was that i’d made a mistake in connecting things up. It certainly doesn’t look half as tidy inside now as i don’t have any of those cable-tidy things but i’m reasonably confident i’ve done it ok.

So, after all this waffle, here are my questions:

having read stuff on the internet i gather cpus can get very hot very quickly but that seemed super-fast and if it was really that hot, would it have cooled down so quickly?

have you heard of temperature sensors having intermittent faults?

assuming it is getting very hot, could it be a dodgy water pump perhaps? would the lack of pumping cause such rapid overheating?
the case felt pretty cool inside when i opened it up.

Any other intermittent faults you can think of?

Any other ideas or suggestions?

Your assumption is correct. 100 celsius is too high.
Something has to be wrong with your watercooler, heat sink, or you have no thermal paste.

in addition since it's watercooled make sure the pump is on, there are no big air bubbles and fluid is moving. (yeah basically something wrong with your water cooler)

Thanks Tarkus.

Since posting I discovered that the molex connector leading from the water pump was a bit dodgy. One of the pins was not seated in the connector and was moving backwards and forwards so that I could see the silver collar near the end of the wire. I've pushed it back in as hard as I could and it all seems a bit more secure now. It's something I shall obviously need to be aware of and take care to ensure a good connection should I need to fiddle with the cabling again.

Thanks again.