The AMD 785G chipset is based off of the very successful 780G chipset, it is basically a 780G with ATI Radeon HD 4200 integrated graphics rather than the HD 3200 graphics found on the 780G. (the AMD 790 GX is pretty much a 780G with HD 3300 graphics) The HD 4200 adds DX 10.1 capabilites, along with onboard HDMI, 1080p, and Blu-ray 1.1 playback. The 785G has also been upgraded from the original 780G to support AM3's DDR3 capability.
The M3A785GMH/128M is a fairly basic but very nice AMD mATX board. The fixtures are color coded with blue, white, red, green, and orange on a deep blue PCB. I really don't care about colors on a motherboard, but I'll have to say that the orange CPU cooler fixture and the green PCI-E slots do clash.though you won't see the PCI-E x 16 slot when a video card is installed.
Overall, as you will see in the following photos, the board is laid out quite well for an mATX motherboard. As many connectors as possible are located around the perimeter of the board, and only two of the three USB ports aren't. There are two fan headers besides the CPU_FAN, with an mATX board you often get only one.
The NB cooler is fairly large for an ASRock motherboard, and quite large for an mATX board. I think that it is pretty innovative, if you'll notice, the pin-fins are of two heights. The shorter ones are to accommodate installation of a card in the PCI-E x1 slot. I'm sure this isn't the first motherboard to utilize such a configuration, but it is the first I've seen.
The CPU socket area is typical, with a large number of ferrite chokes, large capacitors, and MOSFETs located near to hopefully catch some exhaust CPU cooler air. The Socket supports AM3, and due to pin configuration an AM2 CPU will not fit, nor will it work if the two offending pins are removed. For whatever reason, Tom's Hardware has tried that already. The memory controller on the AM3 processor is totally different, and though the new AM3 processors are backwards compatible, the motherboards do not support AM2 processors.
I guess the only weird thing to me on the entire motherboard is the 4-pin ATX12v connector, I have gotten very accustomed to seeing 8-pin connectors. But since this motherboard accommodates only one video card, there is no need for an 8-pin connector, so ASRock didn't add one. Less circuitry means less cost.
In the expansion department, the M3A785GMH/128M has one PCI-E x 16 slot, one PCI-E x1 slot, and a pair of PCI slots. Notice how nicely the connectors are placed at the bottom edge of the board. You usually don't get that with mATX motherboards. There is even a COM1 port. I know that most people don't use them anymore, but I have a couple of unusual items, including a PC Cassette Deck that requires them.
The M3A785GMH/128M has five internal SATA 2.0 slots, and supports RAID 0, RAID 1, RAID 10 and JBOD. It does not support RAID 5, which is one of the very few differences between the AMD 790GX and 785G chipsets. I've never used RAID 5, so that is irrelevant to me.
If you'll note at the top of the photo, there are three internal USB connectors on the M3A785GMH/128M. Few full ATX motherboards I have owned have more than two. This allows for six extra USB ports, giving a total of ten, impressive for an mATX board.
The board supports up to 16 gigs of DDR3 memory, of course a 64-bit operating system must be used for the system to utilize more than around 3.2 gigs of system memory. It natively supports up to DDR3-1333, and will run up to DDR3-1600 with the CPU overclocked.
The I/O panel is well equipped for an economy minded mATX board. Here we find a PS/2 keyboard port, 4 x USB 2.0 ports, 1 x LAN port, HD Audio, and Sub-15, as we'd expect. Not so expected is DVI, HDMI, and eSATA II. I was a little concerned about only having four I/O USB ports, but I looked at a dozen other AMD mATX motherboards, and all of them had four onboard USB ports.and only two internal USB connectors.
The bundle is pretty sparse, what I'd expect in an economy board, just what you need to get started.