Video Card DDR3 on a DDR2 motherboard

Is it feasible? Is it a waste to do this?

I had heard that the 8600GT was a good card, but that you should get the DDR3 version. But, I am thinking the DDR3 motherboards are more expensive so was thinking of a DDR2 board.

Another question, What if I am using DDR2 Ram?

I was not able to use an AGP DDR2 VisionTek Radeon XT 1550 on a DDR motherboard (AsRock 775VM800)
I didnt know that, I assumed that if its AGP at least 8x an AGP video card would work..maybe its this mobo, its a value board I had to buy while waiting on ASUS to RMA my P5P800se.. (still waiting )I am now giving up on that architecture and getting a PCI-E 2.0 Motherboard