Overclocking

To find the maximum overclock of our card we used a combination of GPUTool and our benchmarking suite.
The overclocks listed in this section 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 827 MHz core (7% overclock) and 1202 MHz Memory (20% overclock). Memory overclocking is working well, even though the memory chips are not cooled by any sort of heatsink (other GTX 580 cards reach around 1170 MHz). I find the core overclock a bit disappointing, considering we have seen GTX 580s at 835 MHz, 847 MHz and 895 MHz. In the hands of a pro these cards can work wonders, Shamino recently ran an ASUS GTX 580 Direct CU II at 1519 MHz.

Overclocked Performance

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


The actual 3D performance gained from overclocking is 4.6%.

Temperatures

Even though the card is super quiet, temperatures are still low. This means that there should be decent headroom for heavy overclocking with voltage increase or fan speed reduction for less noise.

Voltage Tuning

It has been a long known fact that overclocking headroom increases as soon as you increase the operating voltage. Until recently, software voltage control on VGA cards has been the exception and most users were not willing to risk their warranty by performing a soldering voltmod. Nowadays almost all current graphics cards have voltage control in order to achieve low power consumption by lowering voltage when in idle or slightly loaded.
In this section we will increase the GPU operating voltage step by step and record the maximum clock speed possible. Voltage is listed as the value that the voltage regulator reports via software, not actual measured voltage. The card was installed in-case, with fan settings at the default, memory will not be overclocked either. If a card has thermal throttling we will reduce the operating frequency to keep performance at maximum for a given voltage. Please note that the fan profile will have an effect on observed temperatures: if the card gets hotter the fan will ramp up to reduce temperatures or keep them from rising fast.

The following graph shows the overclocking potential we saw on our sample. GPU clock is represented by the blue line, which uses the vertical clock scale on the left. The scale starts at the default clock to give a feel for the overclocking potential over the base clock. Temperature is plotted in red using the °C scale on the right side of the graph. An additional graph shows the full system power draw in orange measured at the wall socket when running at the given voltage, clock & temperature.



With the regular BIOS and even ASUS SmartDoctor you are limited to a maximum GPU voltage of 1.15 V. After modifying the BIOS I could reach 1.21 V, but based on the graph above this is still not the limit for the GPU on our card. Such a linear increase is usually followed by a drop at some point where the ASIC just won't gain any more with more juice, my guess is that would be around the 1.35 V mark (you'd need to manually set 100% fan speed to keep the card from overheating).

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.