Two cards, one PCB
The flurry of graphics-card announcements from NVIDIA and AMD in the preceding five months is now coming to an end. AMD has brought a number of new GPUs into the Radeon HD 6000-series fold while NVIDIA has launched the GeForce GTX 580, 570, and 560 cards. Indeed, there's only the ultra-high-end Radeon HD 6990 to go.
A lack of genuinely new GPUs means that both companies' partners have to do something outlandish with present GPUs to really grab the enthusiast's attention. PowerColor is pinning its hopes on the PCS++ 6950 2GB - the premier card out of five Radeon HD 6950s in PowerColor's stable, of which four feature custom heatsinks - to provide this magic X factor.
You see, the AMD-original HD 6950 and HD 6970 cards are disarmingly similar in appearance, and the simple reason for their shared provenance rests with the underlying architecture that's practically the same in both cases. Drill down and you realise that the HD 6950 is composed of 1,408 shaders while the HD 6970 groups 1,536 shaders and higher clock speeds.
PowerColor's PCS++ uses AMD's dual-BIOS option to bridge the gap between the two cards that, in bone-stock form, attract retail pricing of £230 and £280. Interesting? You bet, but let's get the examination out of the way first.
The gargantuan heatsink uses a mixture of heatpipes and aluminium heatsinks and fins to keep the GPU cool. PowerColor has a long history on designing better-than-reference coolers and this one is no exception. Solidly built and with a reassuring heft when handled, the company uses the same big-ass heatsink on its pre-overclocked HD 6970 card, intimating that it has more than enough cooling ability on tap.
The industrial-looking cooler houses two 88mm fans that push the heat away from the GPU, though not all of it escapes out of the back. Rather, the semi-open cover design means that a significant portion of hot air is recirculated around the chassis.
While there isn't a whole heap that's reference about the card, the outputs are. What you're looking at is two DVI - single- and dual-link - HDMI (v1.4a), and two DisplayPorts (v1.2). Depending on how you plumb it out, four displays can be driven simultaneously.
Chunky monkey, sure, and the cooler's potential can be taxed by increasing the voltage to the GPU.
The one obvious difference between reference Radeon HD 6950 and HD 6970 cards lies with the power plugs. PowerColor opts for an HD 6970-matching six-pin-and-eight-pin layout, and you'll see why in just a second.
Tucked up by the two CrossFire connectors is a tiny switch that toggles between two BIOS settings. On the one hand, the card is a regular HD 6950 2GB, clocked in at 800MHz core, 5,000MHz memory, and imbued with 1,408 shaders. Switch the PC off, flick the switch, load up the driver - the card is identified as a new model - and the PCS++ becomes a hybrid Radeon HD 6950 and HD 6970, complete with 1,536 shaders. Confused?
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The left-hand GPU-Z shows the card in its default state. The right-hand screengrab shows a Radeon HD 6970-matching 1,536 shaders and 880MHz core, though the card isn't quite a full '6970 because the memory speed isn't increased to the requisite 1,375MHz. We're adamant that PowerColor would receive a stringent slap on the wrist from AMD if it served up a full-fat HD 6970.
PowerColor says it is able to create this card by taking advantage of the fact that an initial number of Radeon 6900-series GPUs are practically identical at source. Activating the extra shaders and bumping up the core clock is relatively easy for now, thanks to AMD not requesting manufacturing partner TSMC to fuse the separate GPUs' shader-blocks, but this may well happen in the near future. Indeed, custom BIOSes can be download that match PowerColor's 6950-6970 trickery, though you do it at your own risk.
The upshot of all this jiggery-pokery with the GPU is a card that, at a flick of a switch, assumes the form of a near-complete Radeon HD 6970 2GB. Expected to retail from £240 - there are two versions: with and without Call of Duty: Modern Warfare 2 - and therefore attracting just a small price premium over a regular HD 6950, it's an interesting proposition alright.
