Carmack Says Dedicated Physics Processing Units Unnecessary

[Acanthus]

Originally posted by: Extelleron
If physics is so bandwidth intensive, then why does the PhysX card only have 733MHz effective memory on a 128-bit bus, for 11.7GB/s of memory bandwidth, and why is it only on a PCI bus that provides very little bandwidth compared to PCI-E? The PhysX card provides less (theoretically) than DDR2-800 in a dual-channel setup, which would provide 12.8 GB/s. DDR2-1066 would provide 17GB/s.

And if that isn't enough, from X-bit labs:

The processor is equipped with the GDDR3 controller that communicates with the memory via the 128-bit bus. The memory frequency is 366 (733) MHz and the peak memory bus bandwidth equals 11.7GB/s. While top-of-the-line contemporary graphics cards boast over 50GB/s memory bus bandwidth, this number is relatively small, but AGEIA PhysX is very unlikely to suffer from insufficient memory bus bandwidth. Firstly, the PPU doesn?t need to transfer textures (which eats up a lot of memory). And secondly, AGEIA physics accelerator supports regular 32bit PCI interface with 133MB/s bandwidth, so it will turn into a real bottleneck much sooner than the local memory on the accelerator card.

So because PhysX is designed like sh!t (which you can tell from its performance) then it doesnt need the performance that isnt there?