GeForce FX 5900XT core

At its heart the GeForce FX 5900 XT is based on the same NV35 graphics core as the GeForce FX 5900 128MB and GeForce FX 5900 Ultra. This is also the same core that encompasses NVIDIA’s GeForce FX 5950 Ultra. If you recall, NV35 is based on TSMC’s 0.13-micron manufacturing process containing 130 million transistors. NV35 is a four pixel pipeline with two texture units per pixel pipeline (4x2) architecture, supporting NVIDIA’s enhanced CineFX 2.0 engine (which boasts enhanced shading performance) Intellisample HCT, and NVIDIA’s UltraShadow technology (which offers enhanced stencil buffer performance provided the software title is coded to take advantage of it).

NVIDIA’s GeForce FX 5900 XT reference specification initially called for a 400MHz core clock frequency, the same clock speed as the GeForce FX 5900 128MB, but the spec has since been loosened to 390MHz.

We’ve found that this variable can vary from manufacturer to manufacturer (two of the cards in this roundup were clocked at 400MHz by default). With the core clock frequency even varying on 5900 XT boards from the same manufacturer: while many of the early 5900 XT cards were clocked at 400MHz, some of those same cards are now shipping at 390MHz. For those of you worrying about picking up a 390MHz card, don’t worry. The 10MHz clock difference won’t significantly hamper performance.

Reference 5950 Ultra compared to Gigabyte 5900XT

In order to further reduce costs, NVIDIA and its board partners use a slightly less exotic board design (including a single slot cooler) and slower, less expensive DDR memory for the 5900 XT.

The 5900 XT’s memory operates at 350MHz (700MHz effective), 75MHz below the 5900 Ultra and 125MHz slower than the 5950 Ultra. This provides the 5900 XT graphics core with up to 22.4GB/sec of peak memory bandwidth, the same figure as ATI’s RADEON 9800 PRO 256MB and 8GB/sec more than GeForce FX 5700 Ultra, which was the previous leader in this category in the mainstream segment.

Despite the slower memory frequency (700MHz effective versus 850MHz), the 5900 XT is able to keep up with the GeForce FX 5900 128MB in many benchmarks thanks to the lower memory timings its 2.8ns BGA memory boasts.

Due to the reduced frequencies of the graphics core and memory, 5900 XT board manufacturers are able to utilize a simpler board design with reduced power and heat requirements. An external power source is still needed, but the board requires significantly less power circuitry and smaller coolers. Video input and hardware monitoring functionality are also sometimes left out in order to further reduce production costs.

Now that we’re a little more familiar with the graphics core, let’s take a look at the GeForce FX 5900 XT cards that we’ve collected!