Friday 3 July 2015

Overclocking your GPU

Overclocking your GPU

Last, but certainly not least, the final hurrah of overclocking

With DirectX 11, at least, OCing the GPU is the area of most benefit to gamers. But it’s also where overclocking has most dramatically changed. That’s because, with Nvidia’s GPU Boost and AMD’s Power Tune, it’s no longer possible to simply up the voltage and in turn increase cards’ core clockspeeds.

It’s now often better to ignore the voltage and let the proprietary software do its own thing. This way you can avoid reaching the artificial power limits set by our GPU overlords – cores won’t throttle themselves in an attempt to control imaginary temperatures, that may or may not be present, even if they’re running on an aftermarket cooler, or water. Sounds ridiculous, right? You’re not wrong. Still, we’ll show you how far you can go with these cards.


1 Get the software


Unlike CPU overclocking, we need to download some proprietary software to use within Windows. It’s usually most beneficial to download whichever manufacturer’s software your card’s PCB is based upon. GPU Tweak for Asus, Afterburner for MSI, and so on. In this case, we’re using a reference cooler on our GTX 980, so we’re using MSI’s Afterburner. It provides frame monitoring for benchmarking, a customisable display and in-game overlays to monitor how the cards perform compared to their stock speeds.

2 Enable monitoring


Once Afterburner is installed, the first thing we want to do is enable ingame overlay, and frame rate monitoring, followed by (for us at least) changing the skin to something a little more workable.

3 Test stock speeds


Next you’ll want to get a clear understanding of how your card performs at stock speeds. We’re using Total War: Rome II’s benchmarking software at max settings at 2560 x 1440. We achieved a minimum frame rate of 19, a max of 61, and more importantly an average of 44.7.

4 Increase the power limit


We now need to get into the overclocking side of things. Head back to desktop and open up MSI Afterburner again. The first thing we’re going to increase is the power limit. Move the slider to as high as it will go. This should allow our card to use absolutely every inch of power we can get, beyond Nvidia’s recommended stock settings, meaning the card can run all the way up to 91 degrees Celsius, as opposed to the stock 79°C.

5 Up the clockspeed


Start by increasing the clockspeed. Research what’s most suitable for your card. In our case, a healthy overclock for the core clock should be an extra 225–275MHz offset, so we go for 240MHz.

6 Now, the memory clockspeed


Lastly, we’re going to increase the memory clockspeed. After research, we can see the community, on average, is aiming for around 450MHz. We’ll try that and see how it goes, leaving Nvidia’s GPU Boost to calculate exactly how much voltage we need. All that’s left to do is press ‘Apply’ and go back into the benchmark to see how the card performs.

In the Total War: Rome II benchmark, we achieved a minimum frame rate of 17 at overclock, a maximum of 67, and more importantly an average of 53.6, an increase of almost 9fps towards that average. Granted, the delta between the minimum and the average is considerably greater than the stockclocked version, but who can argue with free performance?