I was pretty sure it was 24 lanes, but I recalled X79 to have 40, so I guessed it was 20.
Do you really think a 4960X is better for gaming than a 4790K? I doubt it, even if clocked at the exact same speed. It's the same at best. And then there's price/performance.
You can easily run 780Ti SLI on 1150, especially if you have an ROG (any ROG) board from ASUS. You will see exactly 0 FPS drop if you run it at 8x + 8x, rather than 16x + 16x.
I know SLI isn't the same as CrossfireX, but I've run quad HD 5770 1GBs in a variety of configurations on an older 790FX motherboard.
Also an overclocked 6950 2GB crossfire configuration in 8x + 4x. No drop compared to 16x + 16x.
He will save hundreds of dollars by going 1150, he will have SATA express, M.2 etc, and we will lose 1-2 FPS at most with everything taken in to account.