Introduction

As we noted in our ASUS Extreme X1800 XT TOP review, the story of the R520 GPU in ATI’s Radeon X1800 lineup shares many similarities to NVIDIA’s ill-fated NV30 and the GeForce FX 5800/5800 Ultra line.

Both GPUs were based on entirely new designs and manufactured on untested cutting-edge manufacturing processes (in the case of X1800, with R520 packing over 300 million transistors, ATI’s engineers felt that producing a chip with such a large die on anything but 90-nm was impractical) and both were banking on high clock speeds to achieve much of their performance.

The Radeon X1900 XTX

Radeon X1900 XTX and GeForce 7800 GTX 512MB

The one common trait that’s earned both of them so much notoriety however has nothing to do with the architecture or technology behind either GPU, instead it’s much simpler – both products were notoriously late to market. It has been reported that ATI received their first R520 samples just days after the Radeon X850 launch in late 2004, with ATI hoping to have final silicon ready in time for an early summer release right around the time NVIDIA successfully launched their GeForce 7800 GTX in June 2005. While ATI was quietly demo’ing R520 up and running at tradeshows such as E3 and Computex, the hardware was nowhere near final. ATI wasn’t hitting anywhere near the clock speeds they were shooting for, so the GPU’s 3D performance wasn’t up to snuff.

Radeon X1900 XTX (top) and Radeon X1900 CrossFire (bottom)

Radeon X1800 CrossFire and X1900 CrossFire. Can you tell the difference?

Once ATI resolved the issue it was late summer and NVIDIA’s GeForce 7800 GTX and newer 7800 GT GPUs had gained a significant foothold of the market. Both of these cards delivered dramatically more performance than anything else on the PC and did so with aggressive pricing and solid availability for the entire summer. Ultimately ATI’s R520 products, the Radeon X1800 XT and X1800 XL, didn’t hit the market en masse until November, nearly one year after ATI had received their first R520 chips.

By the time November rolled around though, ATI delivered a hotfix driver that offered improved OpenGL performance. As a result, R520’s performance in OpenGL titles such as Quake 4 and Doom 3 blossomed, allowing the Radeon X1800 XT to surpass the GeForce 7800 GTX in performance. Right around the same time the performance picture was improving, street prices on Radeon X1800 XT and X1800 XL boards began to drop. Soon ATI had a pretty hot product on their hands!

All that’s pretty much a moot point now though, as today’s Radeon X1900 launch makes the X1800 family old news. With 48 pixel shaders onboard, the Radeon X1900 sports twice as many pixel shaders as any previous GPU. But does all this add up to a significant improvement in performance? Let’s find out.