We have confirmed the 24 pipelines rumors from several independant sources. However, these 24 pipelines are not comparable to 24 of today's pipelines - multiply by 1.3. So the 24 pipelines will have the performance of 32 "normal" pipelines.
The result of this is that the R520 will be two times as fast as the currently fastest X850s.
http://www.techpowerup.com/reviews/Cebit2005/Day4/5
Also goes into detail about ATi's SLI technology and how it differs from nVidia.
While NVIDIA SLI splits the screen into two parts and one GPU renders each half, ATI's solution breaks the screen into little squares.