Wednesday, September 14, 2005

AnandTech's R520, RV530 & RV515 Pre-NDA Extravaganza

The part that everyone wants to hear about is, of course, the Radeon X1800 based on ATI's long awaited R520 GPU. Due for introduction later this quarter, the 90nm R520 will be a 16-pipe, 16-shader processor design with a number of different SKUs based on the GPU. Internal ATI documentation specifically claims that the R520 series will ship at launch, just as NVIDIA's 7800GTX and 7800GT series shipped and launched on the same dates.
Common features to all R520 based boards include the new 90nm lead free manufacturing process, a Xilleon based TV encoder, SM3.0, H.264 decode acceleration and CrossFire support. Also expect to see HDTV options for all 90nm ATI cards in the near future, although they may be limited to the All In Wonder series for R520.

At the top end is the Radeon X1800 XT; this 16-pipe R520 will feature a 600MHz core clock, with a 256-bit memory bus connected to 512MB of GDDR3 memory clocked at 700MHz. The 600MHz core clock will give it a lower fill rate than the GeForce 7800GTX (24-pipes at 430MHz), while the 700MHz memory clock will give it more memory bandwidth than the stock GTX (600MHz). Much like the GTX, the X1800 XT will be priced at $599. The X1800 XT will feature two DVI outputs with HDCP support. The lower fillrate seems alarming at first, but consider several factors. First of all, ATI's traditional core design can do "more" per clock cycle (at least on the R420 design) than NVIDIA. Secondly, R520 has a lot of little tweaks including hardware asissted H.264 decoding. Just last week, we also received details about ATI's revamped memory controller which operates on an internal 512-bit ring bus. There is a lot to speculate about performance, but even with similar fill rates as NVIDIA, there is a strong possibility that other workings in R520 will differentiate the card on a real world performance level.

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