I'm working on a realtime application that requires to elaborate a digital video stream 25fps. Algorithms are very time consuming and an hardware parallel solution can help to satisfy time constraints.
Finally I decided for a mixed SW and HW that consists in a TI DSP and a Virtex-5 connected togheter on EMIF.
Initially I choosed a Virtex-5SX, because it has a large number of DSP blocks and a good number of logic cells (usefull for parallel hardware implementations), but on the net I saw that people tend to use Virtex-4FX as co-processor for TI DSP. I suppose that this choice is strictly related to the presence of an hard core PowerPC on Virtex-4FX, but I'm not sure.
In addition I didn't found any reference design for EMIF interface in Virtex-5 (there are only for Virtex-4 or Virtex-II). Could be this a good reason to choose a Virtex-4 instead of Virtex-5?