Seemingly Stable System Occasionally Won't POST

[Eagle784]

I've run dual Prime95 (1 blended, 1 short) for 14 hours successfully, yet every so often, the computer won't post (no beeps) and my motherboard automatically unoverclocks my machine and reboots.

Pentium D 915 overclocked to 3.78 GHz (42C idle, 57C Full Load)
OCZ 2x512MB DDR2-800 @ CL 3-3-3-8
Gigabyte DS3 motherboard

Anyone know what the problem could be?

 

[Maximilian]

I dont think theres any such thing as a "seemingy stable" system. Its either stable, or it isnt. Try running at a slower speed or stock and see if it still does it.

 

[theteamaqua]

D 915 should be able to do 4.1GHz without any vcore added, id stock vcore... and 4.5GHz max from what i have seen on air cooling, tower 120

 

[Duvie]

Random wont post symptoms in the past have been due to flaky mobos.....A power up issue or something...Do they ever happen from warm reboots or only cold starts or after complete shutdowns???

 

[Eagle784]

It doesn't do it at lower clock speeds. However, since this seems to be the machine's only hangup, I'm reluctant to lower clock speed further. (Already lowered it from 4.0 to 3.8 because of this issue, and matters improved decently)

It will barely get to 3.2 GHz on stock Vcore; it's set to 1.5125 in the BIOS, but Vdroop issues usually have it around 1.44 during full load. This seems on par with many other users' experiences with the D 930, however.

Pretty much exclusively happens from warm reboots.

Thanks for your help.

 

[Duvie]

It is likely due to the inability of the mobo to deliver the vcore at initial bootup....In the old days of northwood overclocking I had some boards like this and the way I got around it was to do a pin mod and set the desired vcore I want manually....The danger in this is if the VRMs are not up to snuff you can toast the board....
. In that situation basiaclly waht was happening is the bios was reading and delivering the stock vcore at inital boot and then momentarily into the boot it would up it to whatever I set in the bios...The failure to boot was this result...warm reboots all day as well as reboot at lower vcore set everything back and then do a restart from the bios...Just any cold start was a crapshoot...

What rev does you board say....I plan on using vcore boost and perhaps same mobo you have...It is conroe ready right?

 

[jiffylube1024]

Originally posted by: Duvie
It is likely due to the inability of the mobo to deliver the vcore at initial bootup....In the old days of northwood overclocking I had some boards like this and the way I got around it was to do a pin mod and set the desired vcore I want manually....The danger in this is if the VRMs are not up to snuff you can toast the board....
. In that situation basiaclly waht was happening is the bios was reading and delivering the stock vcore at inital boot and then momentarily into the boot it would up it to whatever I set in the bios...The failure to boot was this result...warm reboots all day as well as reboot at lower vcore set everything back and then do a restart from the bios...Just any cold start was a crapshoot...

What rev does you board say....I plan on using vcore boost and perhaps same mobo you have...It is conroe ready right?

Yup exactly my thinking -- not enough voltage during boot. A common problem on certain motherboards.

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OP -- Do you know it's not throttling at 3.8 GHz when in Windows? Try either upping the voltage or lowering the overclock a bit and see if the problems persist.

 

[Eagle784]

The Vcore at startup thing seems likely, except that I mostly have trouble on warm reboots. Cold starts pretty much always work fine.
How do I check board revision number?

I thought throttling only occurred at high temps? the max temp I get is like 58. Speedfan reports a clock speed of 3.8 also. I'll try upping the voltage a bit, it had some good results last time.