Wich Retina ? The Retina BLT Z3 is all right. The Retina Z2 is only of worth when she comes loaded with 4MB (ZIP) RAM so you can remove the RAM and use it in your A3000.
The retina is neither supported by CGX nor P96 so you are stuck with hte cards own RTG-system that makes it just a "better then nothing" card that usualy goes for 20-30 EUR (depending on the amount of installed RAM)
