Core changes

New clock speeds

As we just mentioned, the RADEON 9800 XT is based on the same basic core as the RADEON 9800; only it operates faster. This means that it’s built off the same basic 110 million transistor 0.15-micron core as the RADEON 9700 PRO. The changes introduced with the 9800 architecture bump transistor count up by 5 million transistors for a grand total of 115 million.

Basically, ATI has continued to enhance its 9800 design for operation at higher clock speeds. While the GeForce4 and Matrox Parhelia are both produced on 0.15-micron processes at TSMC (the same foundry ATI uses for its 9800 production), neither core comes close to touching RADEON 9800 in clock speed. GeForce4 tops out at 300MHz and contains approximately 63 million transistors. Parhelia on the other hand, operates at 220MHz and is composed of roughly 80 million transistors.

In comparison, ATI’s RADEON 9800 XT core runs at 412MHz, an increase of 32MHz over the RADEON 9800 PRO. ATI then mates the R360 core with 365MHz DDR memory (730MHz effective), an improvement of 25MHz for the 128MB RADEON 9800 PRO and 15MHz over the RADEON 9800 PRO 256MB with DDR2 memory.

ATI will only sell the RADEON 9800 XT in one memory configuration: 256MB. We’ve also been told that ATI will ship its boards with 400MHz memory modules, so there’s a little bit of room for overclocking built-in. ATI has more plans for overclocking, which we’ll talk about in more detail on the next page.

Other than the new clock speeds, the RADEON 9800 XT is identical to the RADEON 9800. No new features have been introduced from a micro-architecture perspective.

The RADEON 9800 XT reference board

Back of the card

Board design

The design of the RADEON 9800 XT board is an extreme departure from the RADEON 9800 PRO, as you no doubt can see in our pictures. A considerable amount of the board’s circuitry has been replaced with higher quality components -- the most notable example being the voltage regulator modules. ATI has redesigned the board for operation at higher clock speeds; we’ve been told that the parts have been qualified for higher power and consequently to take more heat.

ATI has replaced its traditional aluminum heatsink with a unit composed entirely of copper. Rolled fins are used for increased surface area. ATI then encapsulates the heatsink in a plastic duct. When paired with the cooling fan, a steady supply of air passes over the copper plate and its fins, which then escapes out the side and top of the RADEON 9800 XT card. ATI then places a copper plate on the underside of the card to cool the remaining memory modules.

Air enters through the duct

And goes out across the board here