When you start MSI Afterburner you will see that the Core Voltage slider is inactive. However, the XFX Radeon DD R9 290X 1000M ships with unlocked voltages and to access voltage control all you need to do is head over to Settings and check the ‘Unlock Voltage Control’ and ‘Unlock Voltage Monitoring’ fields. As you can see from the screenshots, the idle voltage is 0.961mV. Maximum voltage during gaming was 1.219mV
Sliding the ‘Core Voltage’ slider all the way to the right allows the XFX DD R9 290X to unlock a few additional mV. Like we said earlier, the card has no trouble maintaining 1000MHz in game tests, but now we wanted to check how it overclocks. We maxed out the fans and ended up with a 150MHz GPU overclock, 15 percent over the reference clock. This is a relatively good score. However, Elpida’s memory wasn’t as keen to overclock, but we still managed to bump it up by 150MHz (600MHz effective). The overclock was noticeable in Crysis 3 and Battlefield 4.