Phenom II x4 955 Black edition

Slayer32163

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Mar 30, 2009
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I am trying to overclock my cpu to 4.0ghz.
I set the multiplier to 18.0x and 1.3625 and it clocks at 3.6ghz

When i set it to 20.x multiplier which is 4ghz, i cant get past the windows start up. i have to keep bumping up the voltage but i dont know what a safe voltage would be.

Amd phenom II x4 955 Black Edition
Sapphire Hd 5850 1gb
4gb ddr3 1600
asus m4a79xtd EVO
BFG 550w psu
cooler master haf 932
 
You don't need rise the voltage for get 3.6GHz, only rise the multiplier till x18 and 1.35V you can get the 3.6GHz stable.

Now, I have my 955 at 3.8GHz with x19 and 1.456V. You don't must pass the 1.5V.
 

You might be an unlucky owner of a below average chip. I heard many owners of 955 stated that they can reach 3.8GHz with stock Vcore.
 


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I think the same, i can hit the 3.7GHz with only rise the multiplier
 
Slayer32163:
well, i have it stable at 1.4625v @3.8ghz, i dont mind because my corsair h50 doesnt even notice the change in voltage

Because H50 is on par with Prolimatech Megahalems which is an overkill for PII-9xx. In addition, there's nothing to worry about if that's the case as the main point of undervolting is keeping the temperature being low.
 
Yeah, i made a stupid mistake, i set the voltage back to normal, booted up and wala. It works at 3.7ghz without voltage increase but that isnt my goal, i try to get up to 4.0ghz but it wont get there without going past 1.5v
 

It is normal as only one of the best 955 chips will be able to do that.
 
Lower your HT link multiplier. If you haven't already set it to 5x for a 1GHz HT link speed. Once you have finalized your CPU overclock then you can begin raising your HT link multiplier to see how high you can get it and keep it stable. Also, don't forget that you have a north bridge voltage (on the CPU) and a CPU core voltage.
 
Short answer, Yes.

1.45v is the recommended highest voltage for air coolers, 1.5 is the cpu's max voltage and its something non air coolers can handle, such as liquid cooling.

Depends on how good your cooler is. Monitor your temps.

On first switch on in the day, check bios for temp, turn comp on and leave for about 5 to 10mins, now check the temp using hardware monitor. This is your idle temp. Now run prime 95 for about an hour and check temp. This is your load temp. If its below 65, your safe, if not then you have a problem.
 
It's like when I fun bench with 4.0-4.1ghz, but I do end up going past the 1.5V limit, though I never reach past 57C @ 1.55V during full load.