what about the 400mhz fsb socket A cpus? they'll run fine on any newer a7n8x, which this almost certainly will be.

if you MUST get a vivo card, i'd have to say go for the best radeon you can buy.

you should be able to get separate cards for sensible money though.

i'd also think about getting a second hard drive, so that when you're editing video and stuff you can bounce the video from drive to drive, rather than reading and writing to different areas of the same drive.