View Single Post
Old 01-07-04, 09:31 PM   #16
StealthHawk
Guest
 
Posts: n/a
Default

Quote:
Originally posted by The Baron
I would hesitate to call the DX9 codepath a mixed mode. Sure, it uses _pp and can mix FP16 and full precision, but it doesn't necessarily mean that the card uses mixed precision (cards that don't support _pp).

I hesitate to called a codepath that might use mixed precision a true mixed mode simply because it isn't necessarily a mix of anything. Also, a mixed precision mode does not offer the enormous performance benefit of the DX8/9 real honest-to-God mixed mode. Weren't the original benchmarks showing the NV cards running the mixed mode about twice as fast as the DX9 codepath?

Yes, Shirley, I'm going to call the mixed precision mode the DX9 codepath from now on, and I will call the DX8/9 the mixed mode.
No. There were benchmarks of NV35 on the true DX9 codepath(full precision) versus the mixed precision codepath. The mixed precision codepath was a lot faster than the full precision codepath.

There were benchmarks of the NV31 using the DX9 mixed precision codepath versus using the DX8/9 codepath. NV35 however, was never ever benchmarked on the DX8/9 codepath.

We don't know how Valve will handle different codepaths, but I imagine cards that don't have multiple precisions like Volari and Radeon will not even have the option to run the mixed mode since there is no benefit.

Valve in their slides and review sites are calling the mixed precision mode the "mixed mode codepath" and are calling the full precision mode the "DX9 codepath."
  Reply With Quote