Moving along, it's now the boards turn to get a viewing. As we mentioned earlier, the board is a Micro-ATX design; however, this is one design we didn't expect to see. Jetway has done a fantastic job. The 24-pin power connector along with the single IDE port powered by the SB750 Southbridge sits behind the four memory slots while the 4-pin power connector is placed between the Mosfet heatpipe and the PS/2 ports.
The board comes equipped with four DIMM slots; however, this is a different configuration than what we're used to seeing with AMD K8 and K10 processors. Why is that? - Well, this board contains two DDR2 memory slots and two DDR3 memory slots. That's right, this is a combo board designed to run AM2+ and AM3 processors. Thanks to AM3 processors supporting DDR2 and DDR3 memory, if you want to you can get this board and use your older AM2 processor and DDR2 memory or put a AM3 processor in and use DDR2 memory, then upgrade to DDR3 later on. It's that simple.
For a Micro-ATX board, there is no skimping on the setup. Using the SB750, the board is able to support up to six SATA data ports and Jetway has made use of all six, though it's a weird setup as there are two red, two yellow and two green. There seems to be no real logic behind this. Right on the bottom there are three switches; a power on/off, reset and CMOS reset button.
When it comes to the power regulation system, the board has a 5 phase voltage control to keep the CPU fed with a stable current. The Mosfets are cooled by a heatpipe assembly and are all solid state components.
Moving to the rear I/O ports, Jetway has a good setup here. First off, thanks to the 790GX chipset being used, you have the option of onboard graphics. To this end there is a DVI-I and CRT D-SUB port as well as a HDMI-out port, allowing you to have full HD video output as well as digital audio output through the HDMI interface.
The rest is pretty standard apart from the single eSATA port at the top of the blue USB tower which is run by a PCI-E controller chip. In a word, this board has just about everything; bar FireWire.
Lastly, it's down to the expansion slots. Now, before we get into it, this board has onboard graphics. But before you all say "yuck", ATI/AMD has finally done something that I wanted to see done with onboard graphics for years. Intel did it a while ago with the i815 boards, but it never took off and this idea is even better again.
What we are talking about is local cache memory for the IGP. Originally Intel designed its i815 to use system memory for the graphics card; nothing new, but they had what was called an AIMM module that slotted into the AGP slot. This had 8MB of 133MHz SDRAM memory on it and allowed the IGP of the i815 to use this memory instead of the system memory. The good point about this was the entire system memory was free, while the bad point was that the IGP was severely underpowered with only 8MB of memory; not nearly enough for many 3D applications.
Moving to today's setup, the 790GX has what AMD calls Sideport memory. This is actually a 128MB GDDR3 memory module soldered to the board. Now, what you can do in the BIOS is set the system to work in three different modes when using the IGP; UMA, Sideport or UMA+Sideport. In Sideport mode, the IGP only uses the 128MB of GDDR3 memory that is attached to the board for the frame buffer. In UMA mode the 128MB of memory is disabled and the system memory is used fully. In UMA+Sideport the IGP uses the 128MB Sideport memory and if it needs any more for storage, it then can dynamically use system memory to help boost its performance.
We didn't do much testing on the IGP setup in this article as we plan to look at it more directly in a later article, but there wasn't much difference between using Sideport+UMA and just Sideport mode. Since the GPU isn't a real intensive 3D setup, it's under a lot more strain in most cases than the RAM.
Moving back to the slots now; for a Micro-ATX board it's rare to see Crossfire support, but Jetway still manages to squeeze it in. There are two PCI-E x16 slots; a yellow and green one. The yellow one (when the paddle card is inserted into the green one) gets all 16 lanes for single GPU mode. Removing the paddle card gives eight lanes to each slot for a Crossfire setup. A single PCI-E x1 slot sits between the two PCI-E x16 slots and a single PCI slot makes up the legacy connection.