We flashed the Gigabyte 990FXA-UD5 bios to the latest version, which you can find here. If you can’t be bothered manually looking for the BIOS files, then Gigabyte include Windows software on their disc which can automatically look online, download and flash for you. Without the latest version installed, the FX9590 didn’t prove stable at all for us.
While the FX9590 was correctly listed, the default clock ratio was set at 20x, giving a clock speed of 4ghz. We did notice the FX9590 would turbo sometimes to 5ghz when a few cores were loaded, but it wasn’t ideal. We simply increased the Clock Ratio to 23.5 to get 4.7ghz. The system was stable … well almost.
We changed the VCore Loadline calibration from auto to ‘high’. Stability was attained at 4.7ghz with both the Corsair H100i set to ‘performance’ mode, and the BeQuiet! Dark Rock Pro 2 on automatic. The BeQuiet! cooler was noticeably less noisy under load. Temperatures at idle were 34 and under load around 52c.
Now that the system was stable, we loaded the Corsair Vengeance 2,400mhz XMP profile. The board would only accept a 2,133mhz frequency, but still not bad.
As AMD claim this is the first 5GHZ processor we were a little disappointed to see that the FX9590 wouldn’t turbo to 5ghz under any heavy load situation, only in single or dual core tasks. We went back into the BIOS for some more tweaking.
We increased the CPU Clock Ratio to x25 to get a final figure of 5.0ghz. Stability wasn’t achieved until we pushed the CPU VCore to a +0.050V setting.
The system was prime stable at these settings and the core voltage showed 1.476V in the BIOS and around 1.49V in CPUz. The validation below shows 1.58 volts as we were pushing it harder to try further overclocking above 5ghz (unsuccessfully), but it was stable at 5ghz with 1.488v as shown in the CPUz screenshot below.
You can get online verification of these speeds over here.
With both Corsair H100i and BeQuiet! Dark Rock Pro 2 coolers the FX9590 would idle around 36c-39c and rise to around 60c under load (room ambient temperature 22c). Any higher voltage for clock speeds above 5ghz would have dramatically negative effects for the load temperatures and stability, surpassing either cooling solution. We are sure there is more headroom from the processor, but it will need some seriously hardcore cooling to get above 5ghz. We also found that the FX9590 would throttle with a lesser cooler also, even at 4.7ghz, so attention needs to be paid to this.