PowerColor X850 XT

This card is hot -- literally. Leave a finger on it and this may induce a wisp of smoke. Fortunately the heat was not released in vain, for every joule came from rendering gorgeous pictures at ridiculous speeds.

ATI's X850 chip (codenamed R480) is the refresh of the X800 released last year. There are no new features as such, but clock speed and memory has been bumped up all thanks to matured manufacturing and Moore's Law marching forward. Despite having the same number of vertex and pixel pipelines as NVIDIA's GeForce 6800 Ultra, the X850 XT is clocked 22% higher, at 520MHz. That's not to say NVIDIA's offering is inferior, its slower clock speed is due to the larger transistor count which provides it with 32-bit floating point support and shader model 3.0 compliance.

PowerColor's design appears to be ATI's reference board with new stickers. The two slot heatsink and fan combination is comparable to the 6800 Ultra but is considerably hotter. During POST, the fan momentarily hits max speed with a significant whir, but winds down rapidly after. Even whilst gaming, it remains quieter than the 6800 Ultra.

We benched the card on the same system (Pentium 4 EE 3.6GHz, 512MB DDR2 RAM) as we did the 6800 Ultra last month. The results are mixed but comparable.

The X850 cruised through 3DMark05 at 1600 x 1200 scoring 3980, 7% faster than the 6800 Ultra's score of 3692.

Doom 3 is not exactly ATI's favourite cut of tea but it managed 47.8fps at 1600 x 1200, a very respectable figure. At the LCD resolution of 1280 x 1024 and throwing on 4x antialiasing and 4x anisotropic filtering produced 43.5fps, only a tad slower than NVIDIA's offering.

We benched FarCry using our in-house script, looping the Bunker level. Using the simpler Shader Model 2.0 settings naturally resulted in better performance than using SM3.0 on NVIDIA's counterpart. The game was highly playable; more than 80fps at 1600 x 1200 and almost as much at 1280 x 1024 using 4xAA and anisotropic.
We tried AquaMark but the card just didn't want to run it. A windows "Exception Memory Violation" would pop up just as the last test completed. Since it occurs at the very end every time, it seems more likely to be an issue with AquaMark rather than with the board.

It didn't seem like a good idea to overclock such a hot piece of silicon. But with little effort, it reached 540MHz core and 590MHz for memory-the equivalent speed of an X850 XT Platinum Edition, ATI's flagship card. Cranking it up beyond 550MHz resulted with heavy on-screen corruption. All in all, at least 10% of extra power can be squeezed out if need be. Even if it does burn the ozone layer a new hole.

The PowerColor package is well thought-out, especially for VIVO buffs. The board includes the Rage Theatre chip allowing TV input and output via composite or S-Video. There's also component output for HDTV signals. With two DVI sockets, the card is also perfect for a decent dual LCD setup.

So which is better, the X850 XT or GeForce 6800 Ultra? They are both exceptional performers for current games. The X850 has more raw horse power while the 6800 has shaders to last. It's similar to the Geforce4 4600 versus RADEON 8500 battle, with the tables turned. History has shown that in the long run, the faster card remains useful for longer, helped by the fact that the slower card hasn't the raw power to put its extra features in action. To that effect, the final nod goes to ATI's sizzling X850 XT.