There’s no doubt in our minds that the HIS Radeon HD 5970 offers superlative performance and extremely high frame rates. The combination of dual AMD Cypress GPUs, each coupled with its own dedicated 1GB pool of fast GDDR5 memory, makes this graphics card one of the fastest we’ve ever tested.

This particular card is based on AMD’s reference design, so the two GPUs clock in at 725MHz, while the memory clock is set at 1GHz. It’s an enormous card, too, at just over 12 inches long. If you buy the card from Newegg, you get a compact PC toolkit, though HIS is looking to expand the toolkit bundle. Also included is a coupon for a free Steam download of Dirt 2, the DirectX 11–capable racing game from Codemasters.

Assuming HIS built the cards to AMD specs, there should be plenty of headroom for overclocking. The beefy cooling system, with its full-length vapor chamber, can dissipate up to 400W of power. Of course, for best results, you’ll want to tweak the card’s voltage. AMD initially offered its own tool for overvolting GPU and memory, but has since withdrawn the utility. However, MSI’s Afterburner tool (http://event.msi.com/vga/afterburner), which apparently works with any AMD-based graphics card, allows you to tweak the core voltage but doesn’t provide a way to alter memory voltage.

Continue reading this review after the jump.