Introduction

Back in February, ATI demonstrated their first 512MB consumer-level desktop graphics card, the RADEON X850 XT 512MB HD. Not one to be outdone, NVIDIA quickly followed with a 512MB graphics card of their own based on the GeForce 6800 Ultra. Chris reviewed BFG’s 512MB GeForce 6800 Ultra variant back in May.

Both ATI and NVIDIA’s case for a 512MB card was similar. The argument was that games were becoming increasingly complex. Not only were more advanced shaders being used more frequently, game developers were also increasingly using high-resolution textures as well as full resolution normal maps. In a .plan update shortly before DOOM 3’s release, id’s Robert Duffy explained that DOOM 3’s Ultra Quality mode loads all textures with no compression (including the game’s normal and specular maps), requiring around 500MB of texture data for a typical DOOM 3 level. Meanwhile in our GeForce FX And DirectX 9 Half-Life 2 Performance article last year, we showed you Half-Life 2’s use of full resolution displacement maps, which were used in the cave walls in HL2’s video stress test.

GeForce 6800 GT and Sapphire X800 XL 512MB

Sapphire X800 XL 512MB poses with first-generation X800 XL card

X850 XT cooling on the Sapphire X800 XL 512MB

With an increasing amount of games using these high-resolution textures, a solution was needed to prevent the graphics core from chugging underneath all this data (this leads to the choppiness you’ll sometimes encounter when you enter large environments in games). ATI’s initial solution to the problem was 3Dc, which brings compression to normal maps. Now a year later they’re following 3Dc up with another solution: integrating more memory onto the graphics card.

Integrating 512MB of memory on the XL

While ATI initially chose the RADEON X850 XT VPU to demonstrate the feasibility of a 512MB card, they’ve ultimately elected to go with the RADEON X800 XL VPU for the first batch of retail 512MB cards. ATI wanted to keep price in check, so it was decided that the X800 XL VPU would be best for the job (keep in mind that the X800 XL ships with less expensive, slower 2.0ns memory modules). To ease the transition to 512MB, clock speeds of the 512MB X800 XL remain the same, at 400MHz core, 490MHz memory (980MHz effective), but ATI has had to make a few changes…

Another shot of the 6800 GT and X800 XL 512MB

512MB board is longer than 256MB card

You can really see the difference here

In order to accommodate the extra memory modules, ATI had to slightly rework the basic 256MB RADEON X800 XL reference design. The most obvious difference is the board’s longer PCB – the X800 XL 512MB is just under half an inch longer than its 256MB predecessor – but ATI has incorporated a few other changes as well, for instance, with more memory modules onboard, the 512MB X800 XL card draws more power. As a result, ATI added additional power circuitry to the board, which in turn bumps the XL board’s power requirements over the 75 watts the x16 PCI-E slot provides. Because of this, the RADEON X800 XL 512MB requires the same six-pin PCI-E power connector as the X850 XT series of cards.

But ATI’s changes to the X800 XL 512MB aren’t limited to the board’s PCB itself, as ATI has also added two new features to the X800 XL 512MB’s repertoire: dual DVI and VIVO. Up until now, both of these features have been optional additions only a handful of board partners have implemented on their boards, for instance, in our RADEON X800 XL Roundup, only the ASUS EAX800XL/2DTV, MSI RX800XL-VT2D256E, and PowerColor RADEON X800 XL boards supported both of these features. Now ATI is requiring that all 512MB X800 XL boards support both of these features.

But Sapphire has decided to go one step further than this, replacing the stock X800 XL cooler with something better: the X850 XT’s heatsink/fan unit!