Broken power supply?

[testbreakdown]

Hello,

My computer recently died, refused to switch on at all. Despite not switching on, the power LED on the motherboard came on and USB devices still had power so I assumed the power supply was fine. I needed to upgrade anyway, so replaced the CPU, mobo and RAM. Now my computer boots but occasionally will BSOD before getting into windows. I'm worried that the old power supply caused my computer to break in the first place and might even harm my new components. Can broken power supplies cause these kind of issues? Should I just buy a new power supply anyway?

Any help appreciated.

[Re-Invented]

You hit the nail on the head cheap power supplies are not the way to go, usually a decent 400w is better than a cheap no name 700w.

Use people like Antec, Corsair, OCZ

Regards
Lee

[testbreakdown]

OK thanks Lee, I'll order a new one today. It was an Akasa 420W I think so not super cheap, but about 3 years old? I expect the odd component to die every now and then but to take down other components at the same time is just rude

Andy.

[oolon]

Sounds like your power supply cannot provide enough power for your new setup, what was your new/old setup did you change for say a P4 to a core i7? Did you change your graphics card as well? Dumb question but did you connect all the power connectors to the mother board, include the ATX 8-Pin power connector and the 20+4 normal ATX cable?

[testbreakdown]

Sounds like your power supply cannot provide enough power for your new setup, what was your new/old setup did you change for say a P4 to a core i7? Did you change your graphics card as well? Dumb question but did you connect all the power connectors to the mother board, include the ATX 8-Pin power connector and the 20+4 normal ATX cable?

I double checked the power connections and everything seems OK.

OLD: ASUS A8N-E, Athlon 64 X2 4800+, 2GB DDR2, ATI Radeon X1900
NEW: Gigabyte P31-ES3G, Core 2 Quad Q9550, 4GB DDR2, nVidia 9500GT

[watercooled]

You say USB devices are powered and a power LED is on - this could be if the +5VSB rail is still working as it is separate to the PSU's main rails. It is possible your PSU failed and took hardware with it so I'd play it safe and buy a new one but stick to good brands. A 450w PSU would be more than enough for that setup or maybe 500w to allow for a future GPU upgrade

[testbreakdown]

You say USB devices are powered and a power LED is on - this could be if the +5VSB rail is still working as it is separate to the PSU's main rails. It is possible your PSU failed and took hardware with it so I'd play it safe and buy a new one but stick to good brands. A 450w PSU would be more than enough for that setup or maybe 500w to allow for a future GPU upgrade

Ahh that would explain it, thanks for the help everybody. New power supply ordered!

[testbreakdown]

New power supply arrived. Still get intermittent BSOD

I ran memtest and got errors. Suspicous, I ran the test again with the RAM in a different machine and got no errors. So maybe it's the motherboard? I'll do some more tests later.

[oolon]

Have you tried down tuning the memory? I had a P4 the memory in that could never run stably at DDR 400 dual channel, if I ran it single or 333 dual channel it check out fine. Though corrupted a number of things before I realised about the problem. Its difficult however to ever trust a computer that as bad memory in the "default" configuration. It does though sound like the board has been damaged, it would be worth checking all the other components before you splash out on a new board, it could be a problem with the CPU. Don't forget, distance selling regulation means you can return an item even if you have opened it within 5 working days of receipt (so long as you haven't broken it) so you could get a board and return it if it does not fix your problem. [Assumption that your based in the UK]

[watercooled]

Which PSU did you buy BTW?

Yeah, it does sound like the motherboard - but it might be something like memory voltage/frequency is incorrect. Have you had any CMOS checksum errors recently (which could indicate corrupted CMOS settings possibly because of a bad battery)? Have a check through BIOS settings to ensure everything is OK.

[testbreakdown]

I think you're both onto something with memory. Taking a closer look at memtest on the problem machine (P31 chipset) showed the RAM was running at 1110 MHz i.e. overclocked, despite me not having changed anything. Interestingly, this differs from what I see in the BIOS which happily shows 1066 MHz @ 2.1v, as per spec. Ever seen a motherboard secretly overclock memory before?

On the machine that showed no memtest errors (P35 chipset), the BIOS and memtest agree, both reporting 1066.

Assuming the memory was overclocked then (and causing my problem), I set the RAM speed, timings and voltage manually, ran memtest again for a couple of hours and now it seems fine. So fingers crossed that was it

Replacement PSU was a Corsair 520W but I'll be swapping that for a Be Quiet 350W tomorrow.

[watercooled]

I think Memtest can misreport RAM clock (my 800MHz DDR2 RAM is reported as 866MHz) but see if anyone else can verify that. Make sure you don't have any 'turbo' modes enabled on your motherboard.

[testbreakdown]

I think Memtest can misreport RAM clock (my 800MHz DDR2 RAM is reported as 866MHz) but see if anyone else can verify that. Make sure you don't have any 'turbo' modes enabled on your motherboard.

Well it certainly reports the chipset wrong (P35 instead of P31) but I think it's right about the speed - CPU-Z reports the same numbers.

Actually I'm pretty convinced now that it's some kind of hardware conflict between this motherboard and RAM. Specifically Gigabyte P32-ES3G and Corsair TwinX 4GB 1066MHz DDR2 CL5. Straight out of the box, it really does appear to overclock the RAM, and I get the unstability you might expect (Prime95 fails almost immediately). I manually set the RAM to spec, and no problems. So far...

Thanks again for the help everybody.