In the past we have found that overclocking the CPU (Central Processing Unit) can be highly beneficial, offering huge performance gains. That said, overclocking is most effective when the right combination of hardware is selected, as certain processor/motherboard combos will work far better together than others. The same is true when tackling graphics card overclocking, as there are some graphics cards that overclock very poorly and others that overclock like champions.

The Radeon HD 5750 has already proven to be quite a good performer, particularly given the price tag. Still, the slightly more expensive and tempting Radeon HD 5770 costs just a fraction more at around $160 and with that you do get a noticeably faster product. The Radeon HD 5770 features a more complex core design, while the core and memory frequencies are much greater.

Still, it is possible to make your Radeon HD 5750 graphics card even faster by carrying out a little overclocking of your own. Overclocking a graphics card is really very easy and because there are no voltage changes to be made when using software to overclock a Radeon HD 5750, also making it very safe.

Depending on which Radeon HD 5750 graphics card you have purchased can make a difference when it comes time to overclock. The standard AMD reference cooler is a dual slot solution that does manage to keep the GPU at a reasonable operating temperature. That said, the heatsink is quite small and there will likely be quite a few cards available soon that will feature improved designs, so be on the lookout for those products as well...

However when it comes to the Radeon HD 5750, the option to increase the core frequency as high as 870MHz exists, while the memory can be pushed as high as 1430MHz. Based on our experiences neither the core or memory will be able to hit the maximum frequencies offered by the Catalyst software, so there is no need to try and dig up any other overclocking software.

Using the Overdrive feature in the Catalyst Control Center could not be easier. The first step is to enable Overdrive and that is done by simply clicking on the check box at the top labeled “Enable ATI Overdrive”. The next step is to work out the maximum stable GPU frequency, which for us was 825MHz. The same can then be done for the memory, and we ended up at 1335MHz.

The next section of the review will cover how to overclocking the GPU and memory in greater detail, as this process should be done in steps. Getting back to the Overdrive function, you will see in our screen shot that there is also a manual fan speed option, though we did not find it necessary to adjust this.

Under full load when overclocked the fan speed never got much above 40% which was quite impressive, particularly given the operating temperature only maxed out at around 80 degrees. Finally the Overdrive feature also provides active monitoring, which covers GPU temperature, GPU activity, and fan speed.

When you do go too far the graphics card will cause the system to crash/lock up or suffer from random errors. Do not panic, this is normal when overclocking, and will not have a long term affect on the system. Often when the entire system crashes or completely locks up, you will be forced to reboot and then re-enable the last successful settings.

Given that you will be overclocking both the graphics cards core and memory frequency, we feel it is best to start with the core. Push the core as far as you possibly can and then back it off 10MHz. This saw us reach 825MHz with our Radeon HD 5750 graphics card. Then the next step was to increase the memory frequency. Using the same method we eventually arrived at 1335MHz, with the core still at 825MHz.

This overclock was proven to be completely stable after a 4 hour continuous loop in FurMark. Pushing the core or memory frequency any higher would cause FurMark to generate graphical errors and eventually fail by completely locking the system up, causing us to force a hard reset. Heat did not appear to be the problem here, and in order to stabilize these overclocks the graphics card would require physical modifications to increase voltage levels.

Graphical artifacts are glitches that can be seen when running the graphics card in a 3D environment. They can be small or large, but regardless, they are a sure sign that the overclock is too aggressive for the graphics card. Therefore if you begin to see artifacts before the system crashes, back off the frequency by roughly 10MHz.

Hardware - Intel Core i7 965 Extreme Edition (Overclocked @ 3.70GHz) - x3 2GB G.Skill DDR3 PC3-12800 (CAS 9-9-9-24) - Seagate 500GB 7200-RPM (Serial ATA300) - HIS Radeon HD 5750 (1GB) - HIS Radeon HD 5770 (1GB) - Palit Radeon HD 4870 (1GB) - Palit GeForce GTX 260 (896MB) - ASUS P6T Deluxe (Intel X58) Software - Microsoft Windows 7 Ultimate (64-bit) - Nvidia Forceware 191.03 - ATI Catalyst 9.10

The overclock allowed for a 20% increase in performance at 1680x1050 in Wolfenstein, which saw the Radeon HD 5750 go from an average of 55fps to a much more impressive 66fps. Furthermore, this meant that the Radeon HD 5750 was now able to match the Radeon HD 5770 in terms of performance. Then at 1920x1200 we saw an 18% increase and again the Radeon HD 5750 was able to match the 5770. Finally at 2560x1600 the overclock delivered a 15% performance boost.

Interestingly, although we did see a 16% performance boost at 1680x1050 when overclocking the Radeon HD 5750, it was still 13% slower than the Radeon HD 5770. Clearly Left 4 Dead performance is more influenced by the amount of SPUs a GPU has, rather than the frequency that they operate at. Still the added performance meant that the $145 US Radeon HD 5750 was now just 8% slower than a GeForce GTX 260 graphics card.

Finally we have Batman Arkham Asylum and again at 1680x1050 we find that the overclock delivers 17% more performance. This performance boost allowed the Radeon HD 5750 to match the performance of the more expensive Radeon HD 5770 graphics card which was impressive, and this was the case at all three tested resolutions. More notably the Radeon HD 5750 was able to deliver playable performance at 2560x1600 once overclocked!

When running the core at 825MHz and the memory at 1335MHz, the operating temperature when under load increased from 75 degrees to 81 degrees. This 8% rise in temperature is nothing to be concerned with as the GPU is still operating well within safe limits. However as we mentioned earlier, if you can find a Radeon HD 5750 graphics card with an improved cooling solution, that would be the way to go if you do plan to overclock.

While we saw an 8% rise in temperature, the system power consumption level also increased by 15 watts, which was a 6% increase overall. Again this is not a significant increase and given on average we received 15% more performance, the extra power demand can easily be justified. It was great to see that in games such as Batman Arkham Asylum and Wolfenstein, we were able to boost the performance of the Radeon HD 5750 to the point where it mimicked Radeon HD 5770 frame rates.

Finally a word of advice when overclocking, never expect to reach a certain frequency, but rather hope for it. Just because we managed to reach a core clock of 825MHz with a memory frequency of 1335MHz, does not necessarily mean you will. Having said that, you may actually beat our overclock! As mentioned earlier, overclocking is best done in baby steps, bump up the core till you find its limits and then do the same for the memory. Finding the limit of one and then the other is much easier than doing both at the same time.

Reviewed By Steven Walton