I'll assume that's the
XFX RX580 8GB GTS version which is fairly common. Although, to be clear, there they make
many models.
The GTS version has a max advertised clock speed of 1366MHz. Which I would assume if you fire up
GPUz your card probably won't hit using "auto" voltage settings. This is because these cards run in to a "power limit" (power/voltage limit and thermal limit are the two main factors in OCing any CPU/GPU), and many cards have their auto voltages set so high, you hit that limit at around 1300MHz (give or take). To get to/above that, you'll need to do one of two things:
- Increase the "power limit" of your GPU. There's a "power limit" slider on AMD WattMan and MSI Afterburner. I believe 50% is the max you can set in either application. This will simply allow the GPU to apply more voltage without hitting the power limits. However, this also results in higher temps.
- Set a manual frequency/voltage curve so that the GPU uses less voltage to hit a given frequency. For example, if your power limit is hit at ~1150mV without any adjustments to the "Power Limit" slider and that corresponds to 1300Mhz, if you make 1400MHz = 1150mV, now you can get to 1400MHz at the power limit. Because you're reducing the voltage used for a given frequency (or > frequency for a given voltage) you're getting more performance for the same power/heat output as stock.
I typed up a guide
here to explain the process of manually setting voltages using AMD's WattMan utility. As I mentioned in that guide, I've found it easiest to create a spreadsheet and scatter plot of the voltages that you've tested as stable to allow you to extrapolate other values along the curve. To get you started, I've put some rough points along the frequency curve so you can apply to the specific frequencies of your GPU (which will show up when you switch from % to Dynamic Frequency in WattMan). Remember, that similar to CPUs, every GPU responds differently to voltages. Some chips need more voltage to be stable at a given frequency than others.
1000MHz = 890mV
1100MHz = 910mV
1200MHz = 940mV (this 940mV is typically an inflection point on the curve, it gets steeper above this value. Notice that values below this are ~25mV/100MHz and values above are 100mV/100MHz)
1300MHz = 1030mV
1400MHz = 1150mV
2000MHz VRAM = 930mV