Looking at the specs, this new MA790FXTA -UD5 board adds USB3 and SATA3 support to the slightly older MA79FXT-UD5P, although its not quite that simple. The older board has 10 SATA ports, all able to run at SATA2 speeds. Six of them (the blue SATA ports) can be operated as a single RAID array or can be used in native IDE or ACHI modes to support independent drives. The remaining four (the white GSATA ports) can be used in a simiar way, as a RAID array (if I'm reading the manual correctly) or as native IDE/AHCI devices. This gives a lot of flexibility to the drive configuration enabling some very complex drive arrays to be created, including two separate four drive RAID arrays plus two single drives. eSATA support (if required) is provided by a separate cable assembly and backplane supplied with the board.
On the newer board the six blue SATA2 ports are still present, allowing for the 6 drive RAID, 4 drive RAID and 2 independents or six independents to be set up. However, the remaining four ports are split between two SATA3 ports and two eSATA ports on the rear, which limits the possible drive arrangements. Also, the older board has eight rear USB2 outlets whilst the new board has two USB2 and 2 USB3 ports, the space formerly occupied by the outer USB ports on the old board being used for the eSATA ports.
This board also supports triple ATi cars in 16x Crossfire mode, although there are warnings about limitations if otuer PCI-e cards are installed that could limit that performance. The older board supports two cards in 16x crossfire, but there are no limitations imposed when other cards are installed.
The new board also supports DDR3 1866 DRAM whilst the old board supports DDR3 1666, however, if I'm reading the specs right, the 1866 support is limited to two slots, so I can't tell what speed the new board would support if all four slots are used.
Aside from these differences, the two boards are similarly matched.
I've got the older board with the 955BE processor and 8GB of DDR31600 RAM and its quick at stock speeds. SATA2 performance per drive is pretty good (I'm not using RAID), although UltraSCSI U320 is noticably faster. However, its not the interface that the limiting factor in most cases, its the drive hardware. Looking at sustained transfer rates, most current SATA2 hard drives cannot maintain the 3Gbps throughput the interface can handle because it simply cannot be read that fast by the hardware. To get sustained 3Gbps throughput you need high end high speed or solid state drives, and they don't come cheap.
So, unless you really need triple crossfire, USB3 or limited SATA3 support, this new board is not a great benefit. Remember, the boards may be almost the same price, but the USB3 and SATA3 products are likely to be considerably more expensive. Also, as you're limited to 2 SATA3 drives, the performance of a SATA3 RAID array on th new board is probably going to be no better than a four drive SATA2 RAID array on the older board. I would say its not worth buying the new board at the moment unless you need or want USB3 and SATA3 support simply because the USB3 and SATA 3 parts needed to get any benefit from it are currently too expensive. Also there is something missing from the new board (the bit the P on the end of the old number refers to), but I can't think what it is.
