Ah, found it. The Intel Z77 chipset supports 6 SATA ports--two 6GBPS and four 3GBPS. On the P8Z77, all six of those ports are provided internally. On the Maximus V, they went a different route. Two 6GBPS and two 3GBPS ports are provided internally by the Z77 chipset, with the extra 2 3GBPS ports being used as eSATA ports. There are two more 6GBps internal SATA ports on the Maximus which are provided by an ASMedia controller. I'm not a fan of that layout. I understand they did it to maximize the number of internal 6GBPS SATA ports, but I'd rather not have to use the ASMedia controller. I only have the one SSD drive, so I have no use for four 6GBPS SATA ports.