Mention the word Gemini to any ATI fan, and you're liable to see them break out in a cold sweat of excitement. For some time now, this code name has been floating around the web, standing for ATI's attempt to follow in the footsteps laid most recently by NVIDIA's GeForce 7950 GX2 parts. That is, offering dual-GPU performance via two cores, but using only a single graphics board. Well in NVIDIA's case, two boards but one single card. Despite many months of hearing whispers about Gemini, and seeing the odd proof of concept board from AIB's at trade shows, we've still been yet to see an actual, final product hit retail shelves... At least until now. - Elite Bastards

Sapphire Radeon X1950 PRO 1GB Dual Card Review

Perhaps unsurprisingly, it's ATI's largest AIB partner, Sapphire, who have been first to step up to the plate with a final, retail Gemini based design, taking two RV570 cores which make up the hugely popular Radeon X1950 PRO, tying them together in a CrossFire configuration with a PCI Express bridge chip on the board, feeding each core with 512MB of RAM and creating the Radeon X1950 PRO Dual graphics card. Of course, this kind of configuration raises several questions, like will two cores on a single board perform compared to a true CrossFire configuration?

The RV570 is the first desktop GPU to be manufactured using the 80 nanometre process, and this core is designed specifically as a replacement for ATI's previous, R580 based, Radeon X1900 series. As we mentioned, each of the RV570 cores aboard the Radeon X1950 PRO Dual is outfitted with 512MB of memory, with clocks set to 580MHz core and 1400MHz memory respectively. The first thing that strikes you as you lift the Radeon X1950 PRO Dual out of its packaging is the sheer size of the board. Not only is it long, but its height is enormous, towering over the face plate at the rear of the card.

To check out the overclocking abilities of Sapphire's Radeon X1950 PRO Dual graphics accelerator, we used ATI's own Catalyst OverDrive functionality to see how it fared. From its default core clocks of 580MHz, we managed to add an additional 40MHz to each GPU core, giving us a final stable clock speed of 620MHz. Our memory overclocking fared even better. Starting out at the stock 1400MHz memory clock, we gained an additional 190MHz, leaving us with a final stable clock speed of 1590MHz effective. Not a bad result at all, considering it features two cores producing quite some heat.

We already know that a single Radeon X1950 PRO board offers great performance, and actualy two Radeon X1950 PRO's in CrossFire offer superb performance. With that in mind, the abilities of Sapphire's Radeon X1950 PRO Dual were never in doubt, with the board offering CrossFire level performance, and even a little better in some cases due to the mixture of 512MB per GPU on-board and the internal PCI Express switch taking the bottleneck away from the motherboard on occasion. Thankfully, it seems that Sapphire have also seen sense on the pricing front, falling in the same range as getting two cards.

At the end of the day though, it's fantastic to see Gemini in action in a retail board, and if nothing else Sapphire should be applauded for doing so with such a high-level part. Sure, it requires a massive PCB and cooler to match, but the simple fact that it works and works well soothes those old wounds opened up many moons ago. It also lays the ATI graphics AIB market open to more similar projects in future. Although it's safe to say we won't be seeing a board sporting two 700 million transistor R600 cores any time soon, could RV610 or RV630 get a Gemini offering at some point?