Modern graphics processor units are capable of incredible feats of computing performance, carrying out staggering amounts of calculations on the fly in order to render photo-realistic visual imagery. But for some users, it's never quite enough. In the quest for better performance and a higher frames-per-second count, many turn to the use of overclocking software to unlock the hidden potential of GPUs, trading stability for heat and higher performance. With a little research and a bit of patience, you too can use these tools to overclock your graphics card!
Overclocking your card can squeeze a decent amount of extra performance from your GPU, Still, before diving in, you should be warned of at least two things:
1. Overclocking may damage or shorten the lifespan of your GPU. You are pretty much running it above the factory-set specifications that are (ideally) balanced to provide stable performance over the GPU's entire lifetime. By upping the performance, you put the card under more stress and heat, which can damage or destroy vital components.
2. As a corollary to that, overclocking your GPU usually voids your warranty, as you're running the device under higher levels of stress than it was optimally designed for. It's not too difficult to overclock safely, but if you do something wrong and toast your GPU, don't expect it to be repaired or replaced.
If those two warnings aren't going to deter you from squeezing more performance out of your graphics hardware, then carry on!
RivaTuner is an old but solid freeware graphics tuning and overclocking tool. Named after Nvidia's old Riva series of graphics cards, RivaTuner provides good options for tuning Nvidia and some ATI/AMD cards. It hasn't really seen much new development since the last stable release, but if you've got an older card, RivaTuner should work like a charm. It's also worth mentioning that RivaTuner is the foundation of two widely well-regarded tools today: MSI Overdrive and EVGA Precision.
Verdict: Good, but a bit dated in interface and ability. Still, if you have an older card, RivaTuner works nicely.
Built around the RivaTuner engine, MSI Afterburner is an all around improvement from its ancestor. Afterburner allows you to tweak your core voltage, core and shader clocks, and fan speed with simple slider controls, as well as monitor your card's vital statistics via a series of graphs on the main screen. You can even fine tune your fan's behavior at various thresholds in order to insure your card always runs cool. Afterburner allows you to set up to five different overclocking programs, which means you can save and switch to particular configurationsettings painlessly. There's also the option to integrate the Kombustor benchmarking tool for one click real-time benchmarking.
Verdict: MSI Afterburner is pretty much one of the top two pieces of overclocking software out there. Loaded with features and really simple to use, MSI Afterburner is an excellent program for novice users or seasoned overclockers to work with.
Another great tool is EVGA Precision X, which fields a very similar set of tweaks to GPU clock, memory clocks, GPU voltage, and fan settings (automatic fan management, user-defined dynamic curve, or lock to a particular speed) while also allowing you to set up to 10 different configuration profiles for your overclocking settings. The interface is slightly easier on the eyes, but that's probably a matter of opinion, really. Other features include the option for a frame rate cap, and a built-in benchmark feature.
Verdict: A similar breadth of fundamental features pretty much makes it a toss-up between Precision X and Afterburner, especially as they're both built from the RivaTuner core. Choose whichever has a UI works for you, or if an odd quirk in drivers keeps you from using the other.
AMD also includes its own overclocking tool, AMD Overdrive, as part of the Catalyst Control Center package of drivers and control software for AMD GPUs. While you don't get as many features to tweak with, such as voltage control, you will be able to tweak the GPU and memory clock, as well as manually set the fan speed or let the card manage the fan itself (no way to set a dynamic fan curve though).
Verdict: Props for being automatically included in the driver packages of AMD cards, AMD Overdrive is a nice tool to start with. If you're an AMD user and you're not as fiddly with the optimizations, Overdrive will probably be enough for you. However, if you really want to do more with your card, shoot for Afterburner or Precision X instead.
ASUS also has an entry in the GPU overclocking software field, ASUS GPU Tweak. The main screen immediately presents you with a wealth of slider bars for core clock, core voltage, memory clock, and fan speed modifications, as well as a handy diagnostic graph. A handy feature of GPU Tweak is that it comes with the GPU-Z monitoring software bundled in, which offers an in-depth look at your card's stats and performance. Other helpful features include the ability to set custom hotkeys, as well as check for BIOS updates for your GPU.
Verdict: A good bag of features, the bundling of GPU-Z, definable hotkeys, and BIOS updating make this an interesting choice worth trying. It feels a bit less polished than say Afterburner or Precision X, but is a solid OC tool.
ATI Tray Tools is a compact (if slightly dated) tool for getting performance from ATI cards. Working out of the Windows system tray, this utility allows you to overclock core, shader, and memory clocks, hardware monitoring and stress testing. You won't have access to some of the features available with other software, such as vidcapping, setting custom fan profiles, or voltage control, which might be a deal breaker for the finicky. However, for such a compact program, it does a good job working on ATI GPUs.
Verdict: Compact yet powerful, ATI Tray Tools is nice to work with if you pack an ATI (duh) GPU.