The AMD Radeon R9 380X Review, Feat. ASUS STRIX

Overclocking

Finally, no review of a video card would be complete without a look at overclocking performance.

With ASUS setting the STRIX R9 380X’s factory clockspeed to 1030MHz – 60MHz ahead of AMD’s reference clock of  970MHz – ASUS is already significantly eating into the headroom available on the card, and the 1050MHz OC mode further cuts into that. We don’t have any voltage control (we can’t even read the voltage) so the card can only be overclocked as far as the Tonga GPU can go on default voltage. Meanwhile ASUS hasn’t touched the memory clockspeed at all, which should mean there’s a bit more headroom there to play with.

Ultimately we were able to push the STRIX R9 380X OC from 1030MHz to 1100MHz on the GPU, a 70MHz (7%) overclock. I fully expect that Tonga could do better with more voltage – and the ASUS cooler could keep up – but at the same time it would take a bad power efficiency situation and make it worse. Otherwise memory overclocking was a bit more fruitful, as we were able to push the card from 5.7Gbps to 6.4Gbps, a 700Mbps (12%) performance increase. Note that relative to the original 7970, the R9 380X has a narrower 256-bit memory bus, so if there are any situations where GCN 1.2’s color compression technology can’t make up the difference, a memory overclock may help to close the gap.

Overall overclocking is good for another 5% performance increase over the STRIX R9 380X's factory overclock. Though enough to be significant, as we guessed base upon the clockspeeds, ASUS has already tapped much of the overclocking headroom available on the card. For reference clocked cards on the other hand, assuming that they can overclock similarly well, this means they can look forward to a total of 10% or so from overclocking.

Since we can't overvolt, the power/temp/noise impact of overclocking is limited. Under gaming workloads the difference is a handful of watts and a nothing for temperature or noise. Otherwise FurMark, with the higher power target, pushes the STRIX card a bit harder, but everything still remains within reason.