SLI spacing help

[STrain]

I just purchased two GTX 970s and opened up my computer to prepare to put them in when they get here. I have a MSI Z87-G45 mobo (http://www.newegg.com/Product/Product.aspx?Item=N82E16813130693) and just realized that with the spacing in my case next to the power supply I do not believe they will fit in the bottom two PCIE slots. Can I put one of them in the upper slot instead of putting them both in the lower two?

 

[clutchc]

You will definitely want to put them in the first two PCIe x16 slots. The bottom slot is only x4 lanes.
Not to mention it will be darn near impossible to connect the FP wiring at the bottom of the board.

 

[STrain]

You will definitely want to put them in the first two PCIe x16 slots. The bottom slot is only x4 lanes.

Just to be clear, I want to use the two that are closest to the CPU? I've read that one of them was only x4 lanes but honestly I don't really know what that means besides it's slower and couldn't figure out which one it was.

 

[clutchc]

You will definitely want to put them in the first two PCIe x16 slots. The bottom slot is only x4 lanes.

Just to be clear, I want to use the two that are closest to the CPU? I've read that one of them was only x4 lanes but honestly I don't really know what that means besides it's slower and couldn't figure out which one it was.

If you look at the pic of the motherboard face-on on the link you posted, you will see that the top and 2nd slots are at x8, x8 lanes with 2 cards, while the bottom slot is only at x4 lanes. If 3 cards are in use, they will run at x8, x4, x4 lanes.

What they lanes are is the number of data paths the video card has to access the buss. The fewer, the lower the data transmission. At PCIe version 3 and 2, 8 lanes is sufficient, because no single-GPU card can yet saturate the bandwidth of the buss at 8 lanes. . But 4 lanes hinders performance.

 

[Entomber]

(counting from the first one closest to the CPU to furthest) on a Z97 board
slot 1 is usually x16/x8
slot 2 is usually x8/x4
slot 3 is usually x4

 

[Mousemonkey]

SLi will not work with 8x + 4x and as such you have no choice in which slots you can use.

 

[clutchc]

+1^
Good point. Forgot about the Nvidia requirement.