PC started to reboot when first turned on, then its ok

SithUK

SithUK

SithUK

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19 Mar 2004
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188
My PC has started to reboot when I first switch it on. Each reboot occurs further in the PC startup process until in the later reboots the windows desktop almost loads before rebooting. Overall it takes about 5 or 6 mins before windows finally loads and stays loaded and stable. When it does the system is rock solid stable. I've left it on for days/weeks and no problems of any kind.

Doing a little bit of research common thinking seems to indicate the PSU, memory, or HD. I've got a seasonic PSU... so I tried removing one of my memory sticks (I have 2). The reboot on startup problem disappeared entirely. I then swapped the stick in the system for the one I removed. System remained perfect. I've run memtest on the memory in single and dual stick combinations and in various DIMM slot configurations. Memtest shows no errors of any kind (I run the tests after a successful system load to ensure I'm only testing the RAM without the reboot problem interferring). The reboot problem returns immediately when I run the two sticks of memory back in together. So I can rule out the HD.

I'm really scratching my head on this one. The nature of the fault (only occuring when first switched on) means that I've been living with it for a year now. I turn the PC on and when I get back from the shower its fine :-)

It is starting to bug me lately though. I've tried upping the voltage to the nForce4 chipset but it does no good (the chipset controls the RAM yes?).

The PC was fine for 2 years after I built it. The problems only started a year or so ago.

System specs in sig.

Looking forward to your advice!

Sithuk

p.s. Strange how I'm finally getting round to posting this since I've been considering a new build with one of these shiny new Ati 4870 cards!

[edit: Sig not showing.. so I'll paste it here: Opt 146 / MSI K8N Neo4 / 2 x 512Mb DDR / Geforce7900GT (vmod) / Seasonic 500W PSU / Dell 24" Widescreen / CPU and gfx watercooled / Antec Sonata]
 
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Is your PC sitting on a overloaded mains splitter?

Just plug it directly to a mains outlet or a surge protected outlet.

I would run memtest on each stick indvidually and then both as a pair, but make sure you have no power problems first.

LaRZ
 
I'm on a surge protected mains splitter yes. I was on one for the first two years as well without issue. I have recently moved and purchased another and the problem has stayed.

I have run memtest on the sticks individually and as a pair without finding faults.
 
Scanned my har disk and no errors reported. Then again, because the reboot error was also present on my previous hard disk I wasn't expecting the new HD (bought about 6 months ago) to be the cause. That, and the fact that when I remove one of my memory DIMMS there is no reboot issue.

What made you think it was the HD?
 
The memory voltage is already at the maximum possible with the m/b (2.85v). This is wholely sufficient for the memory.

I have to stress... the system ran fine for 2 years. Its only been the last year or so that the reboot thing has raised its ugly head.

Why does the reboot problem only occur when there are two dimms in and not with one?
 
Bios is fully up to date, as are m/b drivers.

Will look into BIOS power management settings (I recall an S3 setting or something similar, will check next reboot :)

Any other ideas?
 
Does sound like PSU, it possible has "cold start" issues, can't keep it's voltages on spec.

Try running a V monitoring program as soon as it finally boots.
If it is a cold start issue, then you should see the "tail end" of the odd behaviour just after the successful boot (ie voltages drifting towards their spec values, smoothing out, that sort of thing).

Unless of course it also happens if you do a warm restart from windows, in which case you've got something else going on.
 
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