The need for speed is real when it comes to PC games, where raw performance has a truly palpable effect on your experience's look and feel. Gamers are always looking for ways to increase the performance of their systems, be it through updated drivers or software tweaks, game patches, or even warranty-busting modifications.

New, more powerful hardware is usually needed for the largest performance gains. But regular hardware upgrades can get really expensive, really fast. If you don't have the budget for new gear or are just looking for a bit of an edge, overclocking the hardware you already own can be a great (and free!) option. Processors, system memory, and graphics cards can all be overclocked to boost the performance of a system--sometimes to a large extent. But for games, it's the graphics card that typically has the largest impact on performance, assuming the system already has a decent processor and adequate memory inside.

Intrigued? We'll walk you through overclocking two graphics cards, using some easy-to-use, free tools that'll work on a wide range of hardware. With some patience and a little know-how, an overclocked graphics card--and ultimately a higher-performing system--is only a few clicks away.

Before you begin

There are a few important things to consider before overclocking your graphics card, like cooling, power requirements, and general system stability.

By definition, overclocking a graphics card means running it above its stock GPU and memory frequencies, which will result in higher power usage and heat output. The coolers used on most of today's gaming-oriented cards typically have some built-in headroom to accommodate at least some level of overclocking, but if your card or system already run hot, additional cooling may be required.

System temperatures can be monitored using any number of tools. Most motherboard manufacturers have utilities available to read the thermal sensors on their boards, and your system BIOS will report hardware health data. The GPU-tweaking utilities we mention a little later will all report GPU temps as well. Where the "right" peak temperature lies for each GPU will vary from card to card, but typically, you'll want to keep it around or below the 90-degree Celsius mark.

As we've just mentioned, overclocking a graphics card will result in increased power consumption simply because it requires more juice to run the card's GPU and memory at higher frequencies. As such, if you're already flirting with the upper limits of your power supply (PSU), overclocking may tip it over the edge and cause system instability, or worse--damage the PSU.

If the recommended PSU for your graphics card is 500 watts, for example, and that's what is installed in your system, you may exceed its capacity while overclocking. It's more likely that you have some headroom, however, because the rest of the components in typical systems shouldn't consume that much power. It couldn't hurt to check, though. Cheap power meters that get plugged in between your PSU's power cable and wall outlet will tell you how much power your rig is using. If your system consumes significantly less than your PSU's rating, you'll probably be fine. This handy-dandy PSU wattage calculator can also help you spitball the approximate power usage of your PC.

Further reading: How to pick the best PC power supply

Your system should also be perfectly stable and fully functional before overclocking. A flaky or unstable system, even if it only occasionally acts up, could be a sign of a marginal component, and overclocking may push it to the point of failure.

Before you begin, we'd also suggest updating your graphics drivers and measuring graphics performance to ensure that the overclocks are resulting in worthwhile gains. If your overclock doesn't yield good results in your favorite titles, but your system is running hotter and louder as a result, it may not be worth the effort. The latest drivers often resolve performance issues with newly released games as well.

Finally, keep in mind that overclocking may shorten the lifespan of your graphics card, especially if you crank up the GPU voltage to push frequencies to the extreme. Not touching your voltage and keeping max temperatures lower can help reduce the potential wear and tear of overclocking. Another word of warning: Depending on your card's model and manufacturer, overclocking may technically void your warranty.

Got it? Good. Let's dig in.

Overclocking tools

A number of hardware makers and independent software developers offer free tools for overclocking graphics cards.

AMD builds a tool dubbed Overdrive right into its Catalyst driver suite, which you can find nestled in the performance tab in the Catalyst Control Panel software. EVGA offers a tool it calls Precision, Gigabyte has its OC Guru utility, Sapphire has Trixx, and MSI offers its Afterburner utility, among numerous others. All of these tools are available as free downloads, and many work with a wide range of graphics cards, not just cards from that particular manufacturer.

Next page: The overclocking process, and results from the two graphics cards we overclocked.

We enlisted MSI's Afterburner utility for this project. Afterburner is built upon the Riva Tuner engine, which has been in development for ages. The "Riva" in its name actually alludes to one of Nvidia's early graphics processors that predates the GeForce brand by many years.

Using Afterburner is simple and straightforward: Download the utility from MSI's website, install it, and you're basically ready to go. When the utility is initially launched, it will scan your system and determine if you're using a compatible graphics card. You most likely are--unlike many overclocking tools, Afterburner works with multiple generations of GeForce and Radeon GPUs from any graphics card manufacturers.

When ready, Afterburner will present you with an elaborate interface, featuring a few sliders for altering power targets, fan curves, GPU and memory frequencies, and current clock and temperature data. There's also a voltage slider for tweaking GPU voltages, but that is disabled by default. To enable it, you must enter the Afterburner advanced properties menu by clicking the gear icon visible in the middle of the interface and ticking the boxes to unlock voltage control and monitoring.

For basic overclocking, we wouldn't recommend messing around with voltages. Pump too much voltage into a GPU and you could damage it irreparably. Minor voltage bumps--say in the 1- to 2-millivolt range--are usually safe, but even then there are no guarantees.

Doing the deed

Before you start overclocking your graphics card, run some benchmarks to get a baseline for your unaltered system. We recommend Unigine's Heaven or Valley benchmarking tools. You can also run some in-game benchmarks if you'd like--all of the games tested in PCWorld's massive roundup of GeForce and Radeon GPUs include automated in-game benchmarks that make capturing repeatable data easy.

To use MSI Afterburner to overclock your graphics card, launch the utility and first crank up the power and temperature limits, though you may only be able to increase the power limit on a Radeon graphics card. A boost of 10% on the power target and a maximum temperature limit in the low- to mid-90's Celsius should work for most cards. If you're extremely risk-averse, you could leave both settings alone and continue with the process using the stock voltage and temperature settings, though that leaves potential performance on the table.

During the actual process of overclocking your graphics card, we recommend altering the GPU and memory clocks individually to isolate any possible instability.

Start slowly, increasing the core GPU clock frequency by 10MHz at a time. After you bump it up 10MHz, save the changes, then fire up the Heaven or Valley benchmark and look for system instability or graphical errors--odd color blobs, sparkling flashes of light, or other visual artifacts. If all looks good, bump the card up another 10MHz and repeat the process. Once you notice artifacts, dial it back a bit until they disappear. Jot down the final peak clock speed and reset it back to standard.

Now do the same for your graphics card's memory clock speed.

Once you know the peak frequency for both, set the GPU and memory to those speeds simultaneously and test for stability once again. If everything seems to be working well, go ahead and enjoy the fruits of your labor! If, however, your system has become unstable or you're seeing weird visual artifacts, back the frequencies down a few MHz for both, and test for stability or visual artifacts again.

If your system remains stable while overclocked, but performance actually decreases, reduce the GPU and memory frequencies until performance begins to scale properly. Overclocking a current-generation Nvidia GeForce GTX graphics card requires more tweaking and monitoring than previous products, for instance. that's mostly due to the automatic performance-tuning capabilities associated with Nvidia's GPU Boost, which dynamically increases the graphics card's clock speed until it hits a certain temperature.

Overclocking can get complicated, as you juggle all the variables. In addition to manipulating the power and GPU temperature targets, frequency offset values are used to further compound the clock speed increases that already come by way of GPU Boost. You'll occasionally find that increasing a certain clock frequency (or voltage) may seem to have worked properly, but performance actually decreases due to errors or throttling. You may also find that the actual GPU Boost clock may shoot above or below the designated offset value when the power and/or temperature targets are also increased. If you run into an issue overclocking an Nvidia GeForce card with GPU Boost, you'll just have to play with it until it's (safely) worked out.

The latest Radeon-based graphics cards give users the ability to alter power limits as well, but their clock frequency adjustments are more absolute. In other words, the GPU (or memory) will specifically target whatever clock speed you specify.

The results

We saw measurable performance gains from both of the graphics cards we overclocked for this project.

The AMD Radeon R9 285 showed the biggest in-game performance increases, but the Nvidia GeForce GTX 960 saw the largest clock speed boost in sheer frequency gain. We tested the cards in an Intel Core i7-4960X powered system with 16GB of RAM, running Windows 8.1 Pro x64 and the latest drivers for each card. All tests were run at 1920x1200 resolution, with max image quality settings, and 4x anti-aliasing enabled.

To give you some concrete examples, Nvidia recommends a GPU boost clock of 1126MHz on the GeForce GTX 960. Factory overclocked cards usually boost into the 1300-1400MHz range. Simply by increasing the power and temperature targets in Afterburner, however, the card's GPU frequency regularly boosted into the 1450MHz range. Increasing the frequency offset and the GPU voltage resulted in an impressive 1538MHz peak GPU boost frequency. We also took the on-board memory up from 1752MHz to 1810MHz.

While overclocked, the performance of our GeForce GTX 960 increased measurably, though not majorly. The card's score in the Unigine Heaven benchmark, for example, increased from 916 (18 fps min., 36.2 fps average) to 946 (18.7 fps min., 37.1 fps average). Frame rates in BioShock Infinite and Sleeping Dogs jumped from 69.2 to 75.16, and 40.9 to 44.1 fps, respectively. With that increased performance also came higher power consumption, however. In its stock configuration, our test system pulled about 224 watts from the outlet under load, but that number went up to 246 watts after our tinkering.

The Radeon R9 285's performance increased more dramatically while overclocked. We took the card's GPU clock up from its stock frequency of 918MHz up to 1106MHz, and its memory from 1375MHz up to 1494MHz. In the Unigine Heaven benchmark, the Radeon's score jumped from 938 (17.2 fps min., 37.2 fps average) to 1029 (18.3 fps min., 40.9 average). BioShock's framerate increased from 72.51 to 79.34, and Sleeping Dog's framerate went from 42.8 to 47.6--roughly a 10-percent increase in each game. Like the GeForce, power consumption went up quite a bit with the Radeon overclocked. Our test system pulled 354 watts from the wall with the Radeon R9 285 overclocked. At stock settings, it only pulled 304 watts.

Ultimately, there is performance to be gained by overclocking, but that additional performance will typically result in higher temperatures and increased power consumption. If a few tweaks smooth out your favorite game's framerates, however, it's probably worthwhile endeavor.

Keeping temperatures in check and altering a graphics card's clocks shouldn't be much of an issue. Altering voltages can reduce the lifespan of the card, but the exact amount will vary from GPU to GPU. Just know what you're getting into before you start, and let the faster games begin!