I have an overclocked Q6600 (3.0ghz, 9x333) on Asus P5k deluxe (0603)
It ran stable on Prime95 v25.5 (4 threads 100% load, small fft for more than 12hours)
But fails just one instance (approx 25 % load) of Super Pi v1.5 32M test
It completed 16K, 32K, 64K, 128K, 256K, 512K, 1M, 2M, 4M

16K: completed in 00.179s
4M: completed in 1m 37.124s
8M: failed after 3m 19.413s Loop 21
16M: failed 5m 41.531s Loop17
32M: failed in 6m 18.938s Loop9
All of them one instance runs, and also times vary slightly for different runs..

Memory: 4 x 1 gb Crucial Ballistix Tracer 800mhz (4-4-4-12) FSB>DRAM, 5:6 (333:400)
Os: Vista Ulimate 32bit (3.3gb Ram)
PSU : Rosewell 750W
Load: 56c, Idle: 38c (Zalman 9700NT)
Vcore: Bios: 1.3125v
Vcore Idle: 1.2480v
Vcore Load: 1.2320v

Is my system stable since it passes Prime95 (4Threads 100%) ?
Why is it failing just one instance of Super Pi v1.5 @ 25%load ??? 

Also to note:
Round off was selected on Prime95...& I ran the small ffts test
But priority was set to 1.. From another forum i got the suggestion to set the priority to "10"
Should I run again with Worker thread priority 10 ???

Finally found the solution !!!

I ran Super Pi 32M under stock settings, however it failed.  This lead me to think that it was rather a OS/Program issue than a stable overclock issue.  So I started searching for Vista Super Pi issues.

The windows vista services that affect Super Pi are,

1) Windows Audio Service (this for sure)

2) Themes

3) Aeroglass Interface

 
By turning these off, I was able to run and complete Super Pi v1.5 32M test.

 
1) To turn off  Windows  Audio  Service  ( start> run> services.msc, find Windows Audio on the list , double click and stop it ) Turning off "Windows  Audio  Endpoint  Builder" is not necessary unless you encounter problem.

2) To turn off Themes  ( start> run> services.msc, find Themes on the list , double click and stop it ) this will also make you turn off tune up theme extension.

3) Aeroglass automatically turns off  by turning of themes. (you can check it by right clicking on desktop>Personalize>Window Color and Appearance>Color Scheme )

Another way to disable Audio service:

To disable sound just for SuperPI and then quickly turn it on. Create two .bat files on the desktop

SoundOff.bat:

net stop "AudioSrv"

 
and

 
SoundOn.bat:

net start "AudioSrv"

I found that it is not necessary to run the program as an administrator or Windows XP SP2 Compatibility mode. But I tried both ways, it works.

 
I also found a Super PI  front-end called Hyper PI

The author claims it is pure Super PI 1.5 MOD XS and it is customized for multi-core CPU's: " Run multiple instances of SPI (one for each processor) and configure the priority of the process easily (without Task Manager). Take a snapshot of all instances at anytime with only one click!"

I personally wasn't able to download it becasue of some server problem.
http://home.pages.at/virgilioborges/

So I now declare that my Overclock is stable !!!

Super Dave:

Just curious...what is your Super Pi 1M time?

 I got 17.237s for Super Pi 1M... i guess it is good enough for Q6600 @ 3000 MHZ

grats man and this'll be good info for future vista overclockers

Hi All,

Awesome overclock QuadFusion!

Not sure about the Prime95 vs. SuperPi, but your Vcore looks to be running under stock volts at load; it could due to Vdroop from the motherboard.  

I think the P5K Deluxe BIOS has a Vdroop damper setting, 'CPU Voltage Damper'; if it's there, I'd set to it to enable and try that.

If not, I think your Q6600 should be able to run stable at 3.0ghz on stock volts, but with the Vdroop, you might have to walk it up a little higher for stability.  I'd watch the temps, but think the 9700NT should be able to handle it.  

I think your running short on vcore i run a Q6600 at 1.35 to get 3.4 stable and can get as far as 3.8 with up to 1.55 vcore. Unfortunatly i blew a vm regulator  on the p6n sli i'm running. I can still get 3.4 on the 1.35 24/7 Folding stable without it...lol

It should be said that your board has bad vdrop as was mentioned above so up the vcore 1.35 to 1.36 should get ya stable. Also what are you taken your cpu temps with? You only mention 1 cpu core temp idle and load temp ? I you haven't already give coretemp or realtemp a try and make sure your getting accurate temps.

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