I was just debating between buying two cards and SLI (GeForce 9800 GT HDMI 512MB 256-bit DDR3 PCI Express 2.0 x16 ) it or buy one card thats better and go with that (Radeon HD 5770 1GB 128-bit GDDR5 PCI Express 2.1 x16). Also, what issues can arise with the motherboard if it can run one slot at 16x and the other at only 4x. Below are links to the graphics cards and motherboard im looking at.
Both SLi and Crossfire boards come in x16 + x8 and x8 + x8 not forgetting the rather odd choice of x16 + x4 (for Xfire) so both lanes do not need to be x16, what about the P55 boards that can only do x8 + x8 because they lack an NF200 chip? Or the 650i chipset that only runs SLi at x8 +x8?