Similar to the other response, I can't speak to the 990FX, but one advantage which might be big for you when comparing Z77 to Z87 is the number of SATA 3 ports. I have a Z77 socket and it has two SATA 6.0Gb/s ports. I have one SSD and one 7200 RPM hard drive (that runs 6.0Gb/s), so any other SATA device I end up adding will be limited to SATA 3.0Gb/s. If you plan to have a lot of hard drives and need the fastest transfer speeds on all of them, that might make a difference for you. Other than that, personally I'd go with whatever is cheaper (again, only considering the Z77 and Z87)