940 phenom II black edition

atomicWAR

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hey running an msi k6a2 platinum., A 790FX with the sb600 south bridge....sadly. Was shooting for a 3.8 ghz clock and was wondering what the ball park voltages should be? don't want to boost my HT just the mulitplier. Hate the headaches that comes with over clocking ram (especially since i am maxed at 8 gigs). oh and this is a water colled system....might try for higher clocks if someone has recommendations. anywho a cheat sheet voltage wise near 3.8ghz overclock would be great thanks!
 
Well boards based on the SB750 generally overclock better with ACC enabled. As far as boards with the SB600 go that MSI platinum is among the best at overclocking. Even so 3.8GHz may be hard to achieve without the SB750 even with water cooling. It's just going to depend on your sample so you'll find out when you overclock it yourself.
 

wwebster100

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Have just been down the path of OCing my 940 Phenom. I'm using a Gigabyte GA-MA770 S3P motherboard (not really noted for OCing) and 4GB of Corsair ram with a Gigabyte 4850 1GB card.
Starting at default settings, I cranked up the multiplier to 17.5 and loaded in Windows. Running CPUZ, I achieved 3.4GHz.
Went back to BIOS and wound up the CPU frequency from 200 to 215. Booted up Windows/CPUZ and scored 3.56GHz. It was then I noticed the voltage had dropped off slightly from 1.35 to 1.31 due to the load on the system even at idle. Back to BIOS and cranked up the core voltage by 0.1.
After the next bootup, CPUZ now gives me 3.61GHz and the voltage is where it should be. Temperatures (idle and under load) are no higher than standard. All this is done with supplied CPU fan.
I also dont like messing with memory timings and voltages so I figure this exercise is pretty simple to get a few more bangs out of my bucks. There is probably a little more room to play with but I've erred on the side of caution.
No doubt a water cooled system could handle more since my main concern was temperature.
 

wwebster100

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That looks pretty good, shiftstealth. As I said above, I erred on the side of caution and kept my voltage at the default value (1.35) but had to increase it slightly in BIOS due to the voltage drop which occurs after Windows boots up. All this is done on the original boxed fan supplied with the CPU. I'm not sure how far to push the voltage with these CPUs but temperature (and stability) was always my concern.
The only difference to my settings are you have opted to crank the multiplier up where as I increased the frequency slightly as well. All in all, 3.6GHz is pretty damn good and certainly shows it in bench testing against the stock-standard settings.
 

wwebster100

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Both matter!
High voltage has the ability to break down the layer insulation within the CPU - kind of like arcing between the components and render them useless (permanent damage).
Temperature has a similar effect but over time. Depending on the temperatures will depend on how long. I have my BIOS set to shutdown the computer at 60C.
So, if you run high voltages at high temperatures, you will shorten the life considerably of the CPU. The same goes for memory and north bridge etc if too much volts are pushed through them or letting them get too hot.
 

wwebster100

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I have a friend who is squeezing 4GHz out of his air cooled system and maintaining stability and temps. I haven't actually seen it but I listen to him boast often enough. I have no doubt it is possible given the amount of enthusiasm, time and money he throws at it. He gets right into the nitty-gritty with memory timings, voltages (raising and lowering), frequencies etc (also the 4870 graphics card) until all bottle necks are removed or minimised.
As for you, be happy with 3.6GHz if you have stability while gaming. The 1.45 volts would be as high as I would be prepared to go. If you want to try any higher, try increasing your bus speed to about 205MHz and put it to the test. Stability will then be your governing factor. If thats OK, you could go back and increase it 1MHz at a time. Keep an eye on the temps while doing this. Dont go over 215MHz or it will upset the PCIe frquencies.
 

rav3n

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Ok I have to say this...If you dont knowmuch about overclocking dont do it. Go read about it some more then try it, otherwise your setting yourself up to screw up your system considerably. Believe me, I know from experience.
 

wwebster100

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Thats good advice, rav3n. A few years ago I had a melt-down experimenting with settings and not really knowing what I was doing. Experience can be a harsh teacher!!
MBs and CPUs are a little more foregiving these days with a degree safety built in.
In the case of shiftstealth, he would be better off setting everything to auto in the BIOS and just playing with the multiplier. Things will either work or wont work. Fact is, he'll still achieve better than 90% of a "finely tuned" system.
 

shiftstealth

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Yeah i understand the stability and multiplier and the bus and all that fun stuff, just not if since its a newer chip should i treat it any different.


Yeah i had stability in prime95 for an hour then stopped, prime95 temps didnt excede 57C
 

rav3n

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The best overclock for the 940 is about the 3.8ghz mark. Beyond that you have to increase the power heaps and you dont gain any real performance benefits unfortunately:(