Overclocking

To find the maximum overclock of our card we used a combination of GPUTool and our benchmarking suite.
The overclocks listed here were achieved with the default fan and voltage settings as defined in the VGA BIOS. Please note that every single sample overclocks differently, that's why our results here can only serve as a guideline for what you can expect from your card.



The overclocks of our card are 965 MHz core (8% overclock) and 1290 MHz Memory (8% overclock). Both overclocks are not too astonishing, they represent about what you would expect from most HD 5870 cards.



ASUS includes their iTracker2 software with the HD 5870 Matrix. This utility lets you adjust GPU voltage, memory voltage, and VDDCI. In addition to that you can monitor all the voltages available on the voltage measuring points and the power draw of individual components. Overall this is a nice choice of added features and the software is reasonably easy to use.

I tested some quick voltage increases and got a maximum GPU clock of 1020 MHz @ 1.3V and 1012 MHz @ 1.25V. This shows that the card does scale nicely when more voltage is applied.

Increasing memory voltage one other hand yielded basically no improvement at all.

Overclocked Performance

Using these clock frequencies (965/1290) we ran a quick test of Call of Duty 4 to evaluate the gains from overclocking.


The actual 3D performance gained from overclocking is 7.2%.

Temperatures

Temperatures are in a healthy range that also has some headroom for overclocking at air cooling - even with voltage increases. Unfortunately the fan is a tad bit noisy under load, but ASUS found a good balance in my opinion.

Clock Profiles

Modern graphics cards have several clock profiles that are selected to balance power draw and performance requirements.
The following table lists the clock settings for major performance scenarios and the GPU voltage that we measured. We measure on the pins of a coil or capacitor near the GPU voltage regulator.


AMD includes their own overclocking utility with Catalyst Control Center. While easy to use, it also limits the maximum overclock to a predefined limit in the BIOS. This limit may vary from vendor to vendor or product to product. Following are the upwards limits for overclocking CCC gives you.