Introduction

ASUS Extreme X1800 XT TOP card

ATI’s R520 GPU: History repeating itself?

Ironically enough, the tale of the R520 GPU used in ATI’s Radeon X1800 shares many similarities with NVIDIA’s ill-fated NV30 GPU, which was found in their GeForce FX 5800 line.

Both GPUs were based on entirely new architectures. In the case of NV30, NVIDIA was ushering in the era of DX9 graphics, while R520 was ATI’s first graphics part to utilize shader model 3.0. It could also be said that engineers at both firms were shooting for the same basic design philosophy, choosing higher clock speeds rather than integrating more shading units into their respective designs. In the case of NV30, NVIDIA was shooting for the lofty clock speed of 500MHz (most GPUs at the time were stuck around 300MHz), while NV30 was built around a 4-pixel pipeline architecture.

When ATI was developing R520, they envisioned a core clock speed of 700MHz or more, this figure is considerably faster than any high-end graphics product produced to date, while the chip was based on a 16-pixel pipeline architecture. Like NVIDIA, ATI sacrificed shaders in order to hit blazing clock speeds.

ATI Radeon X1800 XT (top) ASUS X1800 XT TOP (middle) and GeForce 7800 GTX 512MB

The ASUS Extreme X1800 XT TOP and a reference X1800 XL card

ASUS X1800 XT TOP is massive in comparison to X850 XT PE

To pull all this off, both GPUs relied on brand new, untested manufacturing processes, both manufactured by TSMC. NVIDIA took the plunge with TSMC’s 130-nm process, while ATI went with TSMC’s 90-nm process.

By now we all know how the story played out for NV30. NVIDIA never could get good yields on NV30 at 500MHz, and the board’s FX Flow cooling ran so loud it was the butt of constant jokes. In addition, the performance of ATI’s Radeon 9700 Pro was superior to GeForce FX 5800 Ultra.

In the end NVIDIA had a part they couldn’t produce in significant quantities that not only ran loud, it also generated an excessive amount of heat and wasn’t faster than the competition. NVIDIA quickly scrapped the GeForce FX 5800 and moved to the more robust NV35 GPU found in the GeForce FX 5900, which solved many of the 5800’s flaws but the damage had already been done and NVIDIA didn’t truly recover until the launch of the GeForce 6800 Ultra many months later.

ASUS X1800 XT TOP sits with the reference 7800 GTX 256MB

Reference ATI X1800 XT and ASUS X1800 XT TOP

This is where the comparisons between NV30 and R520 differ a little. Whereas NV30 suffered from poor performance, noise, and supply issues, the only real setback that’s been nagging R520 is supply -- the chip performs well. While ATI was never able to hit the 700MHz clock speed they were shooting for (opting for 625MHz instead), it’s still a very capable performer, delivering performance superior to the GeForce 7800 GTX256MB in many cases. Only NVIDIA’s flagship GeForce 7800 GTX 512MB runs faster, and this board currently sells for significantly more than the 7800 GTX 256MB or the Radeon X1800 XT.

But what if someone were to produce a R520 card capable of hitting 700MHz? That’s exactly what ASUS has done with their Extreme X1800 XT TOP/2DHTV card. Let’s see how it compares to other X1800 XT cards…