Overclocking - The Basics

Now the fun begins. You want to get maximum performance out of your card, while at the same time ensuring that it is stable (i.e. will not artifact or crash while playing a game or running some 3D application).

After you load your video card’s “default” ATITool profile, enable temperature monitoring in ATITool and set your fan speed to 100% (you may use 50% if you wish, but you won’t be getting the most out of your heatsink/fan).

Overclocking the Core

I am going to suggest starting with the core first: Raise your Core clocks by 10MHz and click “Set Clock” (make sure “3D View” is closed or it might hang the system).

Now open the ATITool “3D View” and let it heat up the card as much as possible. Once you see the temperature is not going up any further (you can tell when the graph starts leveling off), close the “3D View” and raise your GPU another 5-10MHz. Now open “3D View” again and let it heat up the card again. Once the 3D cube starts freezing (as well as your computer) or you start seeing artifacts on the 3D cube, it means that you have reached your core’s limit at the specified voltage.

Now you can do finer testing by reselecting the highest known stable frequency and increasing it by 1 or 2MHz at a time.

If you have done this correctly you have now found your Core’s maximum frequency at default voltage (1.425v). You may choose to skip overclocking the memory if you wish, but I suggest you try and overclock both rather than just the core because both are just as relevant when it comes to performance.

Overclocking the Memory

The memory is easier to overclock because it does not hang up your system or crash if you have gone too far, and if you are quick enough (you will understand this statement once you begin experimenting with the memory).

For the memory I suggest you start off with a 20MHz-25MHz increase initially (using the same steps as above for adjusting the Core frequency, but now you are dealing with the Memory frequency). Once you have made the first jump, let the 3D cube heat up your video card to maximum heat. Once it reaches the highest temperature possible without artifacting, close the “3D View” again and increase your memory clocks by another 10MHz. Repeat this process until you begin seeing artifacts on the 3D cube.

Here is where you have to be quick: if you can close “3D View” fast enough upon spotting artifacts from overclocking the memory on the cube, you can avoid having to reboot your system, and you can lower your memory frequency to what it was before, then you try again (using a smaller increment this time.

This may generate some artifacts on your desktop, but don’t worry. They can be easily eliminated by changing the resolution of your display (I usually set it to a lower resolution then I refuse the changes and that takes me back to my original resolution) or by restarting.

Saving your Overclock in ATIToo

After finding your maximum Core and Memory clocks, you may wish to create a new profile in ATITool just so you won’t have to remember to configure the settings manually next time you want to run your video card overclocked. I called my profile “MaxOCDef”, you may choose to call it whatever you wish. Also, do not forget to save any Fan speed adjustments you have made, because remember what you tested for was how high you can overclock at 100% fan speed.

Of course this does not represent absolute maximum stability because playing a game or running a benchmark maybe more intensive than ATITool’s 3D cube. Usually 5-10 loops of 3DMark05 or a couple of hours of gaming are both good indicators of full stability. If you spot artifacts or the computer hangs up during a game or benchmark while using your overclocked settings in ATITool, you may try lowering your Core or Memory frequencies by 1 or 2MHz.

A note on artifacts (graphical anomalies) and Hang-ups: If you see texture tearing it usually means you need to lower your Core’s frequency, and if you see boxes or “checkerboard” patterns it means you need to lower your Memory frequency. Hangs or lock-ups are almost always a result of a too high Core frequency as well.

And please do not forget what has been mentioned above about PSUs. If you are noticing artifacts when you don’t think there should be any, your power supply maybe the cause. Please make sure you check your PSU specs or test if this is the case (one way is by lowering your system CPU and/or Memory overclock). Of course your video card has limits, so if you think your PSU is not good enough, a more expensive PSU may not improve your overclock.

What has been mentioned so far does not really impact the hardware much and it would be very hard to actually kill your card by following the above procedure.

However the next section actually involves using higher than specified voltages, and if you are not careful enough and do not monitor your temperatures, you can permanently disable your card either from heat or extended exposure to high voltage.