Sapphire Radeon HD 5870 

You have to manually increase the clocks and observe the framerate until you find the point where performance drops.

At resolutions lower than 1900 x 1200, 2 GB has very little performance benefits.

Crossfire dual, triple and quad configurations are supported to improve performance even further.

In addition to that you can monitor all the voltages available on the voltage measuring points and the power draw of individual components.

The next GPU-Z version will also be able to monitor voltages and current on this controller.

ATI Eyefinity setups, where the GPU has to draw three different display outputs, the extra memory does come handy in some games.

8.9The HIS HD 5870 iCooler V Turbo is a rock solid card that can play every game you throw at it, at resolutions up to 1920x1200, with highest details settings, and some anti-aliasing eyecandy.

Even considering the $20 value of the game, the card feels still a bit too expensive.

I also would like to applaud HIS for their bundled game choice.

Overall this is a nice choice of added features and the software is reasonably easy to use.

GPU voltage is managed by a UP6225 voltage controller, which supports I2C software voltage control up to 1.85 V. MSI's Afterburner lets you adjust the GPU voltage up to 1.35V. Unfortunately you can only change GPU voltage via software, adjusting the other voltages requires a hard mod via soldering.

This little chip is responsible for interfacing with the ASUS software and provides a means to adjust some additional voltages like VDDCI and MVDDC (the VDDC GPU voltage regulator can be programmed directly).

They are high-end cards and that itself comes with a price premium.

The ASUS EAH 5870 DirectCu is quiet for example, and the leader in the quiet high-end segment is clearly the PowerColor HD 5870 PCS.