Compatible video cards?

[Muncher]

I'd be suprised if anyone had an answer to this question, but I'll ask anyways: Are there any imac compatible video cards that aren't offered online as an option?

Also, if I get a 20" iMac with 128Mb of vram, can I swap out that card later for the 256Mb version?

 

[Sun Baked]

Most of the iMacs have used GPUs integrated into the logic board, most of the 128MB vs. 256MB upgrades have been 2 versions of the same logic board.

Which means you can buy a new logic board (which is expensive), or sell the machine machine and buy a new one.

Though I think the iMac 24 introduced the MXM PCI-Express GPU card.