overclocking AND UNDER-volting.... but how far?

[LostBok]

I'm shifting my old PC kit into another box, where it will be an HTPC and media server, on 24/7, so it would be best if I could run it very cool, quiet (and more economically )....

I've reduce the 1.8Ghz 1.35V Opteron165 from a 2.66Ghz over clock on 1.375V to 2.25Ghz (chosen because the RAM will still be running at spec (500Mhz) and HTT at 1Ghz at this speed)... and when shifting the voltage back down, I tried lower than stock...

1.325 seemed fine... so I decided to drop it further, just to see what was possible.

Currently running at 1.25V, it's booted fine (I'm typing this on the PC right now!) and about to run another round of multi-core Super_PI...

How much further can I go before it gets unstable?

[LostBok]

full super-PI run completed...

[mydian]

You may be able to go lower.

With it being real hot here lately I've been playing with my Opteron 170 voltages at stock 2ghz, and it ran prime95 overnight at 1.1 vcore.. I guess I need to try lower.

[LostBok]

okay, we need a race...

points for the % overclock and then a bonus multiplier for the % of your stock voltage you can run it at...

So I'm on 125% (overclock %) x (1.35/1.25)^2 (ratio of stock V : undervolt V, squared - to give it a LOT more weighting )....

so that's 145.8....

you're getting 100% x 1.35/1.1 = 150.6....

I'll have u beaten by close of play today

[mydian]

LOL I haven't messed with mine anymore today but I will.. that or maybe I'll just see how many mhz I can get out of 1.1 vcore.. kind of nice though.. Who needs cool and quiet when I can run the same voltage at stock speeds mwahahaha..

[LostBok]

I'm running cool'n'quiet... but it's helped by the lower voltages - which means it's cooler, therefore it's quieter....

bt w- I "messed up"... got too keen... too many big steps and I overstepped the mark it posted and 1.1V and then I descided to reset and try 1V without stability testing... next thing I know it won't even go to BIOs...

Sensing a CMOS reset "might" be required, I decided to pack in that mini-proj fo ra few mins and then build my new PC (C2Q)... that's done now - just OS tweaking to do, so the ASUS motherboard is going into an old chasis tonight for round two of overclocking and undervolting... maybe with a bit less gusto and more testing this time

[mydian]

Well I tried 1.075 last night and it was a no go.. Prime85 crashed after a few hours so looks like 1.1 is as low as she will go.. not that its bad or something.

[LostBok]

well I've got the new C2Q rig up and running- straight to 3.0Ghz and we'll see how we go after that...

Opteron 165 is now in an old case, withte same mobo, RAM and cooler, but a lower spec Tagan 400W PSU - hopefully this still lets me get near 1.1V - all I've got it to do so far is POST and launch the memtestCD at 1.2V - still need a hard drive, etc in there before I can Prime95 it

Small steps this time and it'll be on my workshop bench, so I can reset the CMOS more easilly