Yes, the X58 MB has the marvell SATA III which act like the SATAII and the intel SATA II.
You can use either SATA port and you only can see the difference between them on benchmark, but not in the real usage. I will recommend to connnect the SSD on intel SATAII port.
Also you can run the benchmark for SSD on either SATA port to see how they are doing but don't run too much, and you want to compare the 4K reading and writing speeds, becasue it can decrease the SSD performance.
Chiming in with a bit of extra info, it's worth mentioning that the bulk of an SSD's benefit for the end user is not in its throughput, but in the IOP rate. Even on a slower SATAII interface, the drive can deliver its full IOPS capability, since that depends only on the controller within the drive, and not the interface between the drive and system.
So basically, even if you have SATA II throughput, the drive will still feel every bit as fast. The only place you'd notice the difference is large load operations, like games (which might make a half second difference in load times).