Architecture Overview

DeltaChrome will be built using TSMC’s 0.13-micron manufacturing process. This makes it the second DirectX 9 part to be announced at 0.13-micron, the other of course being NVIDIA’s GeForce FX. In terms of core complexity however, DeltaChrome is dramatically different than the other DirectX 9 accelerators that have been announced.

While both RADEON 9700 and GeForce FX contain over 100 million transistors, S3 executives state that DeltaChrome will contain just over half the 125 million transistors contained within NVIDIA’s GeForce FX. S3 wants to keep the exact number confidential, but if we’re looking at 80-90 million transistors, that figure would be significantly less than the other 8-pixel pipeline architectures that have been announced. S3 also wanted to make it clear that chip complexity doesn’t revolve completely around transistor count. The number of gates is also very important, although S3 didn’t want to disclose the gate count within DeltaChrome.

Clock frequencies

Naturally, with so few transistors within a 0.13-micron core, you’d expect the DeltaChrome to boast breakthrough clock frequencies. However, S3 is currently only shooting for 300MHz for DeltaChrome. In comparison, RADEON 9700 PRO is shipping today at 325MHz (and with a 110 million, 0.15-micron manufacturing process), while NVIDIA is targeting 500MHz for its high-end variant of the GeForce FX.

With GeForce FX also built off TSMC’s 0.13-micron process and a higher transistor count, we assumed beforehand that DeltaChrome would posses even higher clock frequencies. While we’re sure that there is some variation in TSMC’s manufacturing process (Matrox Parhelia being a good real world example of this), we still assumed DeltaChrome’s clock frequency would be a little higher than 300MHz, after all ATI is already at 325MHz, and they’re at 0.15-micron.

When we questioned S3 about this they stated that they’ve only tested DeltaChrome at 300MHz, but they’re hoping that the final part will be clocked higher. They’re hoping to get good yields on chips as much as 30% faster than the 300MHz goal, with a lower end part(s) shipping somewhere in the 200-240MHz clock frequency range. They’re ultimately planning to release multiple DeltaChrome products in much the same way they launched Savage3D and Savage4 (which eventually ended up with three variants) at multiple clock frequencies.

Again, the specifics of everything aren’t written in stone, as final silicon doesn’t exist yet. But with the 300MHz core clock frequency that is currently planned, DeltaChrome will boast a fill rate of 2.4Gigapixels/second, just shy of RADEON 9700 PRO’s 2.6Gigapixels/sec.

In terms of the memory subsystem, S3 confirmed that DeltaChrome would utilize conventional DDR SDRAM, just like RADEON 9700. The memory interface itself will be 128-bits wide, with peak memory bandwidth topping out at 11GB/sec. Like GeForce3/4, S3 will be utilizing four 64-bit memory controllers to access data, for maximum efficiency. At 11.2GB/sec, this puts DeltaChrome just between the RADEON 9700 (17.6-19.2GB/sec) and RADEON 9500 (8.8GB/sec) series of graphics cards.