Safe Overclock for Stock Phenom II X3 720?

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CatfishRes

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Oct 11, 2008
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Hi there, I recently got the Phenom II X3 720 and while the stock performance is a big improvement over my previous P4, I wanted to try and get a little extra performance out of it. I only have the stock fan for now (sometime in the future when money is more abundant I'll spring for a better one), so I don't expect a huge improvement. So does anyone know a nice safe multiplier and speed to use for a stock-fanned 720 without risk of damaging the processor? I'm going to experiment conservatively later but It'd be nice to know the limits from other users here.
 
Like PsychoSaysDie has said, an increase of 400mhz for Phenom II chips is just right; probably rise temps around just under 10 celcius. Raise it to 16, OCCT for around 5 hours (or until you're comfortable) and raise it some more if you don't mind warmer temps :) I'd stop at 45 celcius tops... stopped at 39 celcius with my Phenom II.
 
ok, i did a noob mistake, i mistook "5" as "15" and i actually underclocked it too low, causing my system to freeze. Luckily, it worked fine after that, back to stock speed.
 
The highest I ever tried going with the stock heatsink was 3.2GHz (16x multiplier) with no voltage increase. I could have probably gone higher but I didnt try it.

Once I got a big heatsink, I upped the multiplier to 17x and it is stable at 3.4GHz with no voltage increase whatsoever. (still at stock 1.3V). Ive tried going to 17.5x but it is not stable.
 
I'm currently at 3.4GHZ stable. I don't know why but when I made the jump from an ECS 780 board to the Biostar 790 - the stability jumped from 3.2GHZ to 3.4GHZ. This OC is on the stock heatsink but the case has 2 80mm rear exhaust fans & 3 aftermarket 120mm fans (1 on each side & 1 directly over the stock hs & cpu fan). The cpu is staying steadily between 27 degrees and 32 degrees Celcius.
 
Safe over-clocking is relative to the user so IMO stability is my measurement of safe.

My 3x cores stability (4hrs of OCCT/Prime95) list using only multipliers + S1283v cooler:

Stock voltage (1.325v) @ 3.3
Light voltage (1.35v) @ 3.4
Medium voltage (1.40v) @ 3.5
*High voltage (1.45v) @ 3.6
*Max voltage (1.50v) @ 3.7

*Significant temperature jump at 3.6ghz.

One thing to note is AMD's website indicated that max voltage for the AM3 720 CPUs is 1.425v. I'm current running 4x cores with 1.40v @ 3.4 to keep the heat down.
 
i'm on 3.2 ghz at stock voltage and stock fan, and that's pretty much it if you don't fiddle with the Voltage or replacing the stock fan.
 
my Phenom II 720 is currently on 3.2GHz (200*16) and on Auto CPU voltage. ran prime95 for about 8 hours without any problems. just wondering if its safe to leave the voltage on Auto ?
 
I have my Phenom II x3 720 BE running stable at 3.67 i jsut applied some as5 to teh heatsink instead of that stock garbage and its running 35 C idle and 52 tops after 5 hours prime95
forgot to mention cpu is at 1.5v stable at 200x18. runs decent at 200x18.5 but not for too long at max load
 
mine so far

37ghz.jpg


http://valid.canardpc.com/show_oc.php?id=818210

 


I want to ask you 2 things:
1st. Do I have to increase a bit the volt to have the 4th core stable? I have unlocked and it the extra core has the same GHz but sometimes stucks and I hear a cont beep from speakers. I made some stability tests including test with AMD Overdrive and no errors.
2nd. When I unlock the 4th core I cannot see the temps per core. Is it a problem or this is the case? My system sees it as Phenom II X4 20

Thank you in advance
 


The per core temps will always stop working with the 4th core unlocked so that is normal - and whether the Voltage needs increasing depends on the Chip - On mine it runs stable at 3.2Ghz. without any voltage increase with the 4th core unlocked :

Stats02.jpg


At that setting it runs 36C idle (individual core temps were 8-10C lower on this MOBO than the CPU temp. while running 3 cores so estimate ind cores @ 28C ) and under PRime95 max temp is 56C. - can run the CHip at 3.4Ghz. stable with a small voltage increase to 1.34V but got used to using 3.2Ghz. before getting my Coolermaster TX3 heatsink so have left it there.

On stock cooling with the 4th core was getting 44C idle and 64C under Prime 95 at 3.2Ghz. so did not go any higher until getting aftermarket cooling and then just increased higher for benching and then reverted to 3.2GHz. for 24\7 use as it seems the best performance platform for my system with a 5770 GPU and only 2 GB. RAM (higher increases do not seem that noticeable vs. the difference between stock and 3.2GHz.)
 
If I 'open' the 4th core and do no oc do I have to increase volt a little in order to be stable?
How can I be sure that my unlocked 4th core is OK and not damaged?

Once more thank you for your vast response!
 


AS mentioned it really depends - some chips will need a bit more voltage while others run fine - Mine runs fine at the stock voltage (though having the 4th core will use more wattage !! - thus producing more heat) - some of the 4th cores are perfectly fine (they just disabled a good core to fill the demand for the chips) and will run at the spec, some were disabled because they could not remain stable at the spec voltage which is why they were sold as triple core CPUs so in order to get those to run stable it sometimes requires a bit more voltage - some will not run no matter what voltage you run the CPU at and are thus unable to be unlocked - so it will vary from chip to chip.

As far as knowing if the core is good - first test is if the system will boot into windows with it unlocked ( if not try a bit more voltage and retest - if it still will not boot chances are it is defective and unable to be used) - next test would be to run several tests that stress the CPU (ie. Prime95 for several hours) to see if any errors occcur meaning there are problems with the core - If it can succesfully run those tests without errors than chances are the core is fine.
 
When volts are set to auto it works at 1.392 volts. Why it gives more volts?
My M/B is GA-MA785GM-US2H. If I set it to manual volts and select normal then ot gives me 1.312 volts. This without oc and 4th core
 
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