Overclocking

With its use of AMD’s new C3 Revision, we were most eager to see how far we could OC our Phenom II X2 555 Black Edition processor. In general, processors using this new revision OC a little further than processors based on AMD’s older C2 Revision. We managed to hit 4066MHz with our Phenom II X4 965 Black Edition last year.

The 555 was another OC’ing champ. At stock voltage, we managed to hit 3958MHz. That’s higher than the max speed we could get with Deneb CPUs exactly one year ago, and this is with no voltage adjustment!

Phenom II X2 555 Stock Voltage

With this in mind, we thought we’d have tons of headroom for OC’ing, perhaps break through 4.2GHz, but unfortunately this didn’t happen. We couldn’t get the CPU to run 100% stable beyond 4080MHz. While we could boot Windows and run many apps at speeds right at 4.2GHz, we couldn’t get everything to run with 100% stability until we bumped the clock speed down to 4080MHz.

4.08GHz

The other chip we were eager to OC was the Athlon II X4 635. Unfortunately though, our particular sample wasn’t an eager OC’er. We only managed to get the chip to run at 3393MHz at stock CPU voltage, an improvement of just 15%. We then cranked the voltage up, but could only get the chip to run at 3567MHz before stability became an issue. We tried higher clock speeds and voltages, but the CPU just didn’t want to cooperate.

Athlon II X4 635 Stock Voltage

Max OC

Of the three Athlon II X4 Propus CPUs we’ve tested in the last four months, this chip was definitely the worst OC’er.

How did its triple-core cousin fare? Not bad. At its rather high stock voltage of 1.42V, we topped out at 3570MHz. With more voltage, we managed to squeeze another 150MHz out of the processor before stability became an issue.

Athlon II X3 440 @3.57GHz

Breaking 3.7GHz with the 440

We obtained the weirdest OC’ing results with the Athlon II X2 255 though. At the default voltage of our particular CPU sample (1.344V), we got the processor to run at a surprising 3705MHz. However, no matter what we tried, we couldn’t get the CPU to run at speeds any higher than 3795MHz, and even that required 1.525V. The CPU just didn’t want to go any further.

Impressive speed for the 255 at stock voltage

Average max OC though