Overclocking

To find the maximum overclock of our card we used a combination of ATITool's successor (work in progress) and our benchmarking suite.



The final overclocks of our card are 715 MHz core (2 % overclock) and 1325 MHz Memory (15% overclock). Yes, that's one insane memory overclock. I tested these clocks in a variety of games and benchmarks and they do work fine. You have to look at these clocks in perspective to the reference design clocks as well. In this case we see an increase of 19% on the core and 20% on the memory. I was genuinely surprised when I saw that the GTX 280 design had that much overclocking headroom left in it.

Please note that due to the PLL design and clock frequency relationships overclocking the GTX 280 is not completely trivial.

• The core clock can not be higher than shader clock / 2. If the core clock goes beyond that it will be set to 1/10th of what is requested. For example if you set 600 MHz with a shader clock of 1200 MHz it will work. But if you set 601 MHz with 1200 MHz Shader, the actual operating core frequency will be a mere 60 MHz.
• I also noticed that if the shader frequency is too high in relation to the core frequency, the card will instantly render artifacts.
• Last but not least, changing the PCI-Express clock frequency, causes the card to change clocks as outlined in this article.

Temperatures

The temperatures are well within a safe range, even overclocking did not increase the temperature that much.