ATI's Radeon X850 XT Platinum Edition Preview

System Setup and Notes, Overclocking

Toe to toe

In terms of comparative performance, the X850 XT Platinum Edition gets to fight its NVIDIA nemesis on PCI Express, 6800 Ultra. I've left out all other boards from the article for a couple of reasons. X800 XT PE performance, relative to everything else, has been compared on our pages plenty of times in the past. X850 XT PE isn't about being an upgrade from X800 XT PE, or indeed any of the other mid-range boards you'll find today. It's about being the fastest graphics card in the world, for the enthusiast with loadsamoney.

ATI conveyed to us a few days ago that it's primarily for the 9800 Pro/5900 XT user that's got a fair bit of cash to blow on a multi thousand pound PC system, not the customer who already has X800 XT PE or 6800 Ultra, or even X800 Pro/6800 GT. A marketing tool for the most part, the small increase in clock speeds enough to give ATI a bit more headroom in the "we're quickest, neener neener" category. But we'll indulge ATI, and our own benchmarking lust, with some performance figures.

So if you want to imagine X800 XT PE's performance, relative to X850 XT PE, multiply the X850 scores by 0.96. Seriously. It's no more than a few percent faster, if at all. A rough 4.5% increase in the combined clocks sees to that.

So to sum up, ATI's fastest vs NVIDIA's fastest, over a few benchmarks, nothing more.

Hardware

ATI Radeon X850 Platinum Edition Reference Board, R480, 256MB, PEG16X, 540/1180
NVIDIA GeForce 6800 Ultra Reference Board, NV45, 256MB, PEG16X, 435/1100
AMD Athlon FX-55, 1MB L2, 2600MHz
NVIDIA nForce4 Ultra Reference Board, Socket 939, PEG16X
1GB Corsair XMS3200XL, 2-2-2-5, DDR400
Western Digital WD360G Raptor, SATA

Software

Windows XP Professional w/SP2
DirectX 9.0c Runtime
AT CATALYST 8-08-rc2-019256e
NVIDIA Detonator Release 66.93
3DMark03 v3.5.0
3DMark05 v1.0.0
Half-Life 2
ShaderMark 2.1
D3D RightMark 1.0.5.0 BETA
Realtime High Dynamic Range Image-Based Lighting v1.2
GL_EXT_reme
FRAPS 2.1

Notes

Verifying the X850's clocks was made doable thanks to Ray Adams, author of ATI Tray Tools. I worked with him (well, gave him some device IDs) to get X850 clock reading and overclocking into a build, during board testing. ATI Tray Tools saw it like this.

Those clocks mean raw fillrate figures and memory bandwidth of 8460Mtexels/sec of single and multi-texture fillrate, and 37.76GiB/sec of memory bandwidth from the GPU to card memory. While the memory clock is short of the out-of-the-box shipping graphics card world record, that engine clock figure and R480's architecture give it the fastest basic fillrate performance in any consumer 3D hardware to date.

Overdrive

ATI have a new Overdrive implementation to pair with X850, provided by the latest CATALYST driver builds. I managed to put it to the test. You're allowed to overclock the card manually now, for the first time in an ATI driver build, and it varies the clocks (never lower than boot clocks) depending on heat. There's also a utility to allow the driver to determine what it thinks are good, safe overclocked speeds.

So X850 XT PE safely installed, I set about seeing how it worked. First you have to unlock the functionality before you're allowed access to the clock changing controls. Clicking the button to start the automatic clock finder up and running. During the testing you can see the clocks being adjusted and the temperature meter moving up and down. Sadly, the utility pushed things too far and VPU recover had to kick in and rescue things. The final clocks it found of 581/621 were a tad optimistic, failing to benchmark properly with anything I had to hand. Here's how it went using ATI Tray Tools.