Computer shuts off during start up

[Necronic]

I recently restated my computer for the first time in a couple of weeks, and noticed that it kept turning off during bootup. It seems to happen right as I dor the 'windows loading' screen. After I unplugged it and cleaned it out I restarted it, this time I got going to the desktop. Everything was running good then it shut off again (within 30 minutes or so.)

I have 4 guesses as to the problem.

1) bad psu.
2) bad motherboard
3) bad sectors on hard drive
4) CPU heatsink not set well and CPU is overheating.

I'm going to go pick up a psu tester and some thermal paste and reseat the CPU/check the psu. What other advice do y'all have? So far I don't see any bad caps on the mobo, but I don't want to start up the computer any more than necessary on the chance it is the PsU and it will fry the mobo.

Here's the specs

Vista 64 ultimate
silverstone 800w psu
radeon 4800x2
intel e3850
can't remember the mothrboard
2x 500 gb western digital cavia. (set up in raid striping. Dear god I hope it's not a bad hard drive. By the way don't run your hard drives striped unless you motor them also )

 

[Cheesy1]

I was recently having a similiar problem due to an old wireless adapter I was using. Uninstalling it and getting a new one solved the problem for me. Don't know if you are using an old wireless adapter or not, but just in case you are that might be something to look into.

 

[Necronic]

Update. I pulled everything apart and it looks like the heatsink wasn't setaed well on the motherboard (one of the clips wasn't all the way in.) I broke two of the clips taking it off. It was one of those heatsinks that come with the psu. I had a nice heatsink sitting around that I hadn't been able to put on last time, so I tried to get it set on there this time. After a lot of 'should I push harder, I don't want to break anything' I finally got it set. Then I went to put the motherboard tray back in and.....the heatsink was too tall to clear the psu.

Good news is I think it's a good bet that this was the problem, plus it gives me an excuse to go hit up microcenter and buy a new one. Good times.

 

[PatrThom]

I did that with some of my old PIII heatsinks. Gave me the excuse to get some nice, quiet ones that keep things real cool.
Wouldn't be the first time I had to modify a HSF to fit.

--Patrick

 

[Necronic]

I went down to microcenter and was surprised to find that it's hard to get any short 775 heatsinks. I was (un)lucky enough to have a really good salesman helping me out, and I went back and forth between buying a crappy low form heatsink, or...buying a new case. It was really tempting to just buy a new case, but the case I have is really nice, if not super functional.

In the end I did something I never thought I would. I bought a 'water' cooling system. Technically it's not water. To be honest I don't know what the he'll is in it (it comes all sealed up), but the pump/heatsink connection was really short and had good mounting brackets so it fit in nicely, so it was probably the best bet even if it was a bit pricey (~80$). I'm still a bit confused about it being self contained though.

After installing it, which was relatively painless, I started reconnecting everything, and realized that YES, I SHOULD have kept track of what goes where. There are a couple cables I am confused about. Particularly why my front fan cables never seemed to have been hooked up before.

I'm going to look it over one more time tommorow, then cross my fingers and turn it on. I can't imagine I messed up any of the connections significantly enough to actually damage the system when I turn it on, and who knows? Maybe I got it right.

 

[Matt²]

Had a 775 heatsink clip set break on me last week.. actually I should note, it was alREADY broken, not by me!
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Anyway, yeah, I had a spare and swapped it out.. old one had been misapplied for a LONG time, burnt a pattern into the wrong side of the old fan, and had been hanging loose for a while too.. finally overheated (202) .. reapplied arctic silver and new fan, and good to go! It also was failing on powering up at a certain point but finally got narrowed down from power supply to overheating.

 

[Necronic]

So I replaced the heatsink with a corsair H50 liquid cooling system. It was pretty easy to get in and a good backing plate/mounting system. Thing is though, I'm still running at 51C under load. Seems a bit hot frankly. Oh well, still runs good.

 

[Seraphyn]

50C under load is nothing to worry about.

 

[Necronic]

I wish I could remember what it ran it before. I remember having to do a bunch of research on CPU temperatures to figure out if the temp was too high. It was interesting, because I remember finding out that a lot of what is thought about CPU temps is flat out wrong. Part of this has to do with how the temperatures are measured. My CPU has 2 cores. The CPU itself (if I remember right) has 3 or 4 sensors. 1 (Tc I think) rests between the two cores, and that is the temperature most people report, the other two (which run much hotter) rest on the core itself or are derived or something. Man, I wish I could remember this.

Basically what I was finding was that you had a lot more clearance for temperature than you thought you did. I even went so far as to look into the technical documentation for the CPU.

...actually I just went and looked that up. The max temperature for 65 W is listed as ~70C. The shutoff temperature is 20C higher than that. Good lord my CPU must have really been cooking.

Anyways, at 50 C I am golden. Actually....I am so golden I may just go and crank up the clock speed