Quote Originally Posted by davexl View Post
I have had this too - I have found that it is an early warning sign that Orthos/Prime won't make it through the night.

As you note, it does not happen when just running the apps - so this is instability caused by the heat/load of Prime95, which stresses the system more way than everyday apps.

Which poses the question - you machine might very well be stable for everyday tasks but you can't prove it!

On these marginal overclocks I can run systool's stability test, and memtest for 12 hours, but the much hotter Orthos/Prime95, it will crash/fail/reboot within a few hours. This could be from heat, or from power delivery problems.

So what is stable? For my godbox, I run a q6600 at a conservative 3456Mhz, which has passed everything I can throw at it, including 48 hour Prime95 Blend. For my renderslaves, I have run them overnight at 3600Mhz running my 3D rendering program just fine, although I know they are not close to prime95 stable.

Q6600/X3220 HEAT AND POWER

At my standard 3456MHz @ 1.5250v bios (damper on)

Running Orthos 8K = 360 watts, 79C Coretemp
Running 3D renderer = 302 watts, 64C Coretemp
idle = 174watts, 44C Coretemp

At my not-P95-stable 3600MHz @ 1.6000v bios (damper on)

Running Orthos 8K = 408 watts, 85C ct
Running 3D renderer = 346 watts, 73C ct
idle = 195 watts, 46C ct

At stock 2400MHz:

Running Orthos 8K = 178 watts, 48 ct
idle = 114 watts, 36 ct


So you can see at the high end that there could be a 50-60 watt difference between everyday apps and Prime95.

And also I have yet to have anything over 3500MHz be Prime95 stable on the P5K.

Notes: all temps at 21.5C ambient, Ultra-120 Extreme, with two undervolted Scythe SFF21F fans in a push -pull config.
good insight?? have anybody tested high fsb and orthos or prime?? do you have the same observations??