To SLI or not?

[oxygene]

Hey chaps just a very quick question. I currently have a geforce GTX 660 and its great for most things. But since getting a 120hz monitor and with the impending release of BF4 I am thinking I should go higher.
My current main thought is as my motherboard is capable how much of a boost would getting another 660 give me?
I've never done dual cards before so I'm new to it, the motherboard lists the below:

1 x PCI Express x16 slots, running at x16
1 x PCI Express x16 slots, running at x4

Does one running at 4x mean I wont get as much speed from it? Will it be significantly lower, and not worth buying it? Or doesnt that affect it in the ways I'm thinking?

 

[4737Joker]

i dont think you can run sli on a 4x slot, doesn't it need to be 8x/8x?

I'm sure someone will be along to clarify this shortly.

 

[oxygene]

Ahh righty, it says AMD crossfire on the mobo page so I just assumed both would run. As I say I have no clue on this stuff lol.

 

[pastymuncher]

Crossfire only i am afraid. If you wanted SLI you would have needed the Z77X-D3H.

 

[oxygene]

Damn.and ive heard amd gpus are better for bf4 qnywwy. But i would hate to miss out on 3d, and that shadowing thing. Looks like i am stwying on the 660 for a bit then cheers for help guys