The XFX DD R9 280X M1000 card is reference clocked, meaning 1000MHz for the GPU and 1500MHz (6000MHz effectively) for the memory. Most buyers probably won’t feel the need to overclock the card, as it already has enough muscle to cope with current generation games, provided the resolution isn’t too high.
However, there are those who will overclock it for fun, or just to show off, in which case it’s what we call overcocking rather than overclocking. Still, there are a number of gamers who might need a bit more performance, at 1440p or 1600p.
In any case XFX did a clever thing by unlocking the voltages and allowing users to squeeze out more performance. The Double Dissipation cooler comes in handy if overclocking is what you’re after. It does its job very well on reference clocks and cooling an overclocked GPU is not an issue for this cooler either.
On stock voltages we were able to achieve only average overclocking results. It could be simply that we were not lucky and we got the GPU which was not willing to work on higher frequencies. However, we then decided to play around with the voltages and after a slight increase we got much better results. MSI’s Afterburner tool (version 3.0 beta 15) works with the DD R9 280X 1000M and allows users to change GPU/memory voltages with relative ease
Without a voltage increase (default 1144mV) we achieved 1065MHz on the GPU but after the voltage increase to 1256mV we scored 1150MHz. We achieved a memory nice overclock of 20 percent (from 6000MHz to 7200MHz) without increasing the voltage.
XFX actually has two bios versions for the card. The second bios, which is practically the overclocking bios, will be available online and it will allow users to flash the bios from Windows or DOS. With the so-called OC bios we managed to get marginally lower results compared to our first run, in which we adjusted the voltages manually, using Afterburner. However, we also noticed a few side effects, such as increased power draw and higher GPU temperature.
With the default bios on reference clocks the GPU voltage does not go over 1.18V.
The OC bios went to 1.25V, even on reference clocks. At the same time the GPU was hotter and the fans were a bit louder.
On the other hand, the OC bios allowed us to boost the clock by 130MHz, while the default bios ran out of steam at 65MHz. We are of course talking about stable clocks, but in some games we could go up to 30MHz higher.
Low GPU overclocking headroom could be the reason XFX is binning GPUs and keeping the better ones for Black Edition cards.