SLI

What's the diffrence in SLI boards I mean there's 16x and 32x for SLI how much of an impacted is that and is it worth it?

You mean 8X and 16X in SLI?

older SLI'ed cards get PCI Express 8x each   
2000 [4000]* MB/s    
newer SLI'ed cards get
PCI Express 16x    4000 [8000]* MB/s

PCI Express is a serial based technology, data can be sent over the bus in two directions at once. Above, the first number is the bandwidth in one direction and the second number is the combined bandwidth in both directions.

So... basically if 1 card has more than 2000MB/s of information to send over the bus, frame rate will be limited.. this usually happens when you run games in extreme resolution and with lots of anti aliasing and high texture details.
In normal operation this limit isnt reached so the new 32x SLI is really only a tickbox feature..