Killer performance at a fantastic price

It’s no secret that ATI’s RV770 GPU, which first appeared in the Radeon 4870 and 4850 last year, is a performance beast. The spring refresh of the GPU, which offers increased core and memory clocks, along with a slight redesign of the GPU, tells an interesting story to anyone who isn’t yet running a second-gen DirectX 10 card (GeForce 2xx series or Radeon 48xx series). However, if you’ve already upgraded, there’s not much to get excited about here.

The Radeon 4890 is built on a 55nm process, just like the 4870 and 4850, but the company made significant tweaks to the architecture to accommodate higher clock speeds, which is evidenced by the fact that Diamond overclocks this board from 850MHz to 925MHz out of the box. Diamond also overclocks the card’s 1GB of memory 100MHz faster than the default, to 1,050MHz. The Radeon 4890 sports quad-pumped GDDR5 memory running on a 256-bit bus. The real stars of the Radeon 4890’s show are its pixel shaders, though, with 800 shader units running at the GPU’s core clock speed. The massive number of shader units gives the 4890 a significant advantage over comparable Nvidia cards in shader-limited benchmarks like Crysis.

The ATI card doesn’t fare as well in memory-limited benchmarks. Even though it’s using more advanced GDDR5 memory than the competition, the 512-bit-wide memory bus on comparable Nvidia cards gives those cards an advantage in games that are fillrate bound, as you can see from our Call of Duty 4 scores.

The wild cards, as has been the case for the last few months, are the proprietary technologies supported by the different cards. On the Nvidia side, you have Nvidia’s general-purpose GPU computing spec CUDA, as well as hardware acceleration of PhysX apps. On the ATI side, you have DirectX 10.1, which improves visual quality or performance in games that support the spec. Fortunately for people shopping for videocards, neither side has a decisive advantage. There are just a handful of consumer applications that take advantage of CUDA, and just a few decent games that support PhysX or DirectX 10.1. By the time any of these technologies are mainstream, you’ll have upgraded this graphics card.

The Diamond Radeon HD 4890 XOC is an extremely capable DirectX 10 card that you can find online for around $250. With a full 1GB frame buffer and enough shader processors to play most demanding games at 24-inch panel resolutions, there’s a lot here to like.

Diamond ATI Radeon HD 4890 XOC

Topaz

Tons of shader power; the fastest single-GPU Radeon you can buy; overclocking headroom.

Emerald

Noisier than a 4870; marginal upgrade from other RV770 GPU boards.

Diamond

Benchmarks

	Diamond 4890 HD XOC	GeForce GTX 285
Driver Version	Catalyst 9.4	182.08
Crysis 4x AA / Very High	22.2	20.32
Crysis noAA / Very High	25.97	24.76
Call of Duty	63.57	74.6
Vantage Game 1	16.4	19.45
Vantage Game 2	12.4	14.26
Far Cry 1920x1200 (High Quality, No Physics, No AI)	51.8	57.91
Far Cry 1680x1050 (High Quality, No Physics, No AI)	56	65.11

Best scores are bolded. Benchmarks are run on an Intel Core 2 Quad Q9770 Extreme, with 4GB of memory running Windows Vista. Crysis, and 3DMark Vantage are run at 1920x1200, with 4x AA and 8x anisotropic filtering, unless otherwise noted. Call of Duty is run at 2560x1600 with 4x AA.