AMD FX-8120 Black Edition CPU Review (with Asus M5A99X EVO)

As you'll have seen on the previous page, Asus have used the same excellent UEFI interface for the M5A99X-EVO that they use on many of their motherboards.  This makes the overclocking process quite simple indeed.

First of all we tried out the automatic overclocking function that Asus has devised.  This can be found on the ‘AI Tweaker' page of the UEFI interface along with all of the other settings for overclocking.  This managed to overclock the FX-8120 to 3.875 GHz using a baseclock of 250 MHz and a multiplier of 15.5x for an overclock of 775 Mhz.

See validation here.

For those who aren't confident enough to manually overclock their CPU, the automatic overclocking function will provide quite a significant boost in performance.

We had mixed success when overclocking the FX-8120 manually.  We managed to push the CPU to 4.2 GHz using a baseclock of 200 MHz and a multiplier of 21x without adjusting the voltages at all.  This is also very simple for less advanced users and is the setting we used for our overclocked benchmark results.

See validation here.

Unfortunately 4.2 GHz seemed to be the limitation of this particular chip as we weren't able to achieve a completely stable overclock higher than this, even when using very high volts of 1.40 – 1.45V.

We were able to achieve higher overclocks which were stable with Prime95 however different types of benchmark such as 3DMark or Cinebench would cause random instability.

We also tried the FX-8120 with a ASRock 990FX Fatal1ty motherboard and HD 6670 and experienced the same 4.2 GHz stability limit with this chip.

So we decided to see how far we could push the FX-8120 in the 990FX Fatal1ty while still getting our system to boot. We managed to achieve a massive 2000 MHz overclock, giving us 5.1 GHz using a baseclock of 200, multiplier of 25.5x and core voltage of 1.475v. We tested with Cinebench for a minute without encountering stability issues. We would be lying to claim it was usable 24/7 however.

See validation here.

For comparison purposes we overclocked our i5-2500K to 4.2 GHz to give a clock-by-clock comparison with the FX-8120.  We also tested the i5-2500K at 4.7 GHz which is the highest we've been able to achieve with this particular i5-2500K chip.

These two settings cover two scenarios. The first being a solid overclock of 4.2ghz, easily achievable with stock air cooling and limited bios knowledge. Then 4.7ghz which requires increased core voltage and enhanced cooling.

See Validations for 4.2 GHz here and 4.7 GHz here.

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