Power Usage And Temperature Benchmarks
The power and temperature tests are where we expect to see some real wins from the liquid-cooled Radeon HD 5870 LCS.
First, let's look at power draw, both at idle and while stressing the GPU with the 3DMark Vantage Perlin noise test at the extreme preset:
First, we will note the extremely high idle power usage of two Radeon HD 4890 cards in CrossFire. An astounding 286W is a level that many passable gaming machines won't even reach under duress. At load, the CrossFire setup is pulling almost twice that, but the overclocked 5870 card with the modified BIOS is pulling even more.
However, the stock Powercolor HD 5870 LCS and the overclocked version using the stock BIOS are pulling much more reasonable load numbers, while providing performance that almost matches the extreme overclock.
This is where the LCS will come into its own. Even pushed to the stock BIOS' overclocking limit, the card remains cooler than 50 degrees Celsius, and it takes the unlocked BIOS flash and high overclock to force load speeds above 50 degrees. Compare this to the CrossFire'd Radeon HD 4890 cards, which idle at 63 degrees Celsius and reach 80 degrees under load.