AMD Phenom II X3 720 BE and Phenom II X4 810 ProcessorsMon, Feb 09, 2009 - 12:00 AM
I won’t be overclocking the AMD Phenom II X3 720 today as I have something special cooling planned for the processor. I put off overclocking till the very end of testing, so if something blows up all the benchmarks are completed. By doing that I wasn’t ready for dry ice till the weekend and my local supplier of dry ice happens to be closed on weekends. To hold you guys over till I get everything ready for some ‘real’ overclocking I did some overclocking on the AMD Phenom II X4 820, which is a locked non-black edition processor.
The AMD Phenom II X4 810 is an interesting processor in that it is locked and has a multiplier of 13x with a default HT clock frequency (bus speed) of 200MHz. With multiplier options ending at 13x I figured I’d just see how high I could crank up the bus speed till the processor needed more voltage.
Without touching any other option in the BIOS other than the HT clock frequency I managed to hit 3.32GHz! This is a 715MHz overclock for doing nothing more than adjusting a single setting in the BIOS! The processor really comes to life at 3.3GHz! I tried to reach over this HT clock frequency, but no matter how much voltage I threw at the processor when using water cooling it just would not load Microsoft Windows and even at with the HT clock frequency at 260MHz it would lock up in the BIOS or on the post screen. This is due to the fact that these processors don’t like to run the HT link past 2600MHz on AM3 cpu’s (AM2+ phenom 2’s tend to stop at 2400MHz). By lowering the HT link and NB link you can then increase the bus speed again. (HINT: The NB link MUST be equal to or higher than HT link).
By doing this and increasing the voltage a CPU frequency of 3.58GHz was reached by increasing the CPU voltage to 1.41V.
Wanting even more, we tossed on the ASUS Triton 81 CPU Cooler and cranked up the CPU Voltage to 1.47V and was able to reach 3.84GHz. This overclock would error on Prime95 after a couple hours, but it ws pretty close to being stable. With a few more hours of voltage tweaking this processor could likely hit the 4GHz mark on air cooling! By overclocking the CPU frequency was increased by 1,235MHz, which is an overclock of 46%!
As you can see benchmarking the overclock shows that it knocked 32 seconds off the ProShow Gold benchmark, which is an improvement of 26.2%.