Testbed and Methods

The testbed was configured as follows:

• Intel Pentium 4 3.2GHz CPU;
• ASUS P4C800 Deluxe mainboard;
• 2x512MB TwinMOS PC3200 DDR SDRAM, CL2.5;
• Windows XP Pro SP2, NVIDIA ForceWare 66.81.

The settings of the ForceWare driver were left at their defaults; the graphics quality settings of 3DMark05 were default, too. The graphics quality settings in the games were the highest, too. I also carried out tests with 4x full-screen anti-aliasing (selected in the settings of Doom 3, Far Cry and 3DMark05) and 16x anisotropic filtering (selected in the 3Dmark05 settings and forced through the driver for Doom 3 and Far Cry). My testing went in an open testbed and without any additional air cooling; the room temperature was about 24..25°C. The temperatures of the GPU and the graphics card were read with the help of RivaTuner.

Overclocking

So, the standard frequencies of the Gainward PowerPack! Ultra/2400 Golden Sample are 350/1000MHz. They are set to 400/1100MHz on choosing the Enhanced Mode Settings in the ExperTool utility. The card was stable at these clock rates at any fan speed, but we certainly should not consider the latter frequencies as the device’s limit.

The maximum frequencies the card was stable at when overclocked by RivaTuner were 430/1200MHz (with the standard cooling system). That’s very good for a GeForce 6800 GT. What’s remarkable, the card went through the whole cycle of tests at such frequencies both at 100% and 50% of the fan speed.

Let’s see what temperatures of the graphics processor and of the PCB RivaTuner reports when the card is working at its regular frequencies. There were two test modes: “Idle” (Windows’ Desktop on the screen, no applications running, the temperature values are written down after half an hour of the system’s being idle) and “Burn” (3DMark05 is running five times in a row with its default settings, then the temperatures are written down). So, here are the results:

The GPU temperature only increases by 14°C in the Burn mode when the fans are working at their maximum speed. If the fan speed is reduced to 50%, the temperature grows by 18°C – that’s very well for a noiseless mode.

When the dynamic control over the fan speed is selected, the Idle temperatures almost equal those at the 50% fan speed, while the Burn temperatures – those at the 100% fan speed. That’s quite natural since the GPU temperature is low when there’s no load and the driver automatically keeps the fan speed low. When there’s load, the core temperature starts to grow, making the driver speed up the fans.