|PowerColor AX6990 4GBD5-M4D Video Card|
|Reviews - Featured Reviews: Video Cards|
|Written by Bruce Normann|
|Sunday, 20 March 2011|
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PowerColor Radeon HD 6990 Video Card Review
Manufacturer: PowerColor (TUL Corporation)
Full Disclosure: The product sample used in this article has been provided by PowerColor.
AMD's new Radeon HD 6990 video card reclaims the top spot in their overall GPU product hierarchy. There is no single-GPU card that can compete with two 6900 series Radeon processors running in tandem. This was also true for the HD 5970, and at first glance the HD 6990 looks like a one-for-one replacement, but is it? Not really; it's better, or I should say it's more better. I'll explain the tortured linguistics in a minute.
Last month we looked at a PowerColor PCS++ HD 6950 video card that used the built-in BIOS switching capability to provide an unbelievably simple upgrade from HD 6950 specifications to full HD 6950 GPU specs, for both clocks and shaders. The Radeon HD 6990 takes a slightly different tack, as the full numbers of shaders (1536) are always available from each GPU. On the 6990, the BIOS switch unlocks the core clock and the GPU voltage for the more adventurous among us. Normally that kind of enhancement-on-a-switch might seem a bit ho-hum, but with the power of two Cayman class GPUs on board, there are physical limits that must be respected. Heat and power go hand in hand and they are the defining elements that shaped the design of this card. Some say it's folly to try and pack this much power into a single package; it's better to have two cooling systems, and two slots, and two sets of PCI-E power connectors to spread the load. They may be right; we'll just have to see... Follow along with Benchmark Reviews as we put the PowerColor AX6990 4GBD5-M4D to the test.