OverclockingTo 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 688 MHz core (14% overclock) and 1237 MHz Memory (12% overclock). Both overclocks are nice, especially for a brand-new product.
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.
It seems NVIDIA has found a good balance between fan speed/noise and load temperatures. Even though the maximum rated ASIC temperature is 105°C, the fan is adjusted in a way to give you temperatures in the 80° range. The idle temperature of 49°C is rather low though. I would have preferred a quieter fan and higher temperatures in idle.