When AMD launched its 780G chipset early this year, it was hailed as one of the best integrated chipsets in the market. Intel was yet to deliver on its newer 4-series chipset then and its older 3-series integrated solutions with its GMA 3100 were obviously not up to the task of taking on the newcomer, especially with its Avivo HD hardware. With its decent integrated graphics performance, the 780G also became the basis for AMD's new Puma mobile platform.
The 780G however is a solely mainstream product, which is why it's proving to be a popular choice among system integrators. Despite this, there remained a product segment gap between the mid-range 780G and AMD's designated enthusiast chipset, the 790FX which is the first 7-series chipset supporting the new Phenom processors and an integral part of AMD's Spider platform.
AMD's reply was to beef up the Radeon HD 3200 integrated GPU (a disguised Radeon HD 2400 PRO) on the 780G by having the same GPU running at a higher core clock. Additionally, this new integrated GPU (known as the Radeon HD 3300) has access to a dedicated memory bank dubbed SidePort memory to ensure even better performance with some local memory. While such a practice is not limited just to the 790GX chipset (for example, Gigabyte has a 780G board enhanced with SidePort memory), it's an almost standard feature now on the 790GX class of boards. Naturally, AMD's Hybrid Graphics is supported so you can pop in a Radeon HD 3450/70 card and enable CrossFireX if you choose to, though we aren't too optimistic about the performance gain.
There's also a new Southbridge, the SB750, which is a minor upgrade to the SB700 Southbridge (addition of RAID 5 functionality) and a decent increase in the number of SATA and USB ports if your previous board is on the SB600. It's not that significant of an increase either way and one could even treat it as a SB600 version 2 effectively.
For the enthusiast however, there's an interesting nugget on the SB750 by AMD in the form of Advanced Clock Calibration (ACC), a new feature which can allow for higher overclocks on a Phenom processor due to some internal mojo that AMD engineers have done and which they won't reveal besides saying that it involves connecting unused pins on the Phenom CPU to the SB750 Southbridge in order to change the CPU's internal timings. This will make it easier to reach some of the higher overclocks long desired by Phenom owners.
So, the 790GX chipset will come with this latest Southbridge and befitting its performance value segment, it will have a pair of PCIe 2.0 x16 expansion slots for CrossFireX (configured to two x8 interfaces when in CrossFire), as compared to a single PCIe 2.0 x16 slot on the standard 780G. And its retail price also reflects this positioning, with the 790GX sandwiched between the 790FX and the 780G in pricing, though in this case, from what we have seen, it's probably closer to the 780G chipsets.
In any case, we managed to get our hands on two 790GX + SB750 motherboards from Foxconn and MSI recently and we tested both out in our labs. Before we delve into the individual boards, here are the technical specifications for both:-
|Foxconn A7DS-A||MSI DKA790GX Platinum|
|Chipset||AMD 790GX + SB750||AMD 790GX + SB750|
|No of DDR2 DIMM Slots||4 x DDR2 (Up to 1066MHz, 8GB max)||4 x DDR2 (Up to 1066MHz, 8GB max)|
|PCI Express 2.0 Slots||
|ATA-133 Ports (chipset)||1||1|
|SATA 3.0Gbps Ports (chipset)||6 (1 eSATA)||6 (1 eSATA)|
|USB 2.0 Ports (header)||12 (8)||12 (6)|
|FireWire||2-port VIA VT6308S||1-port Jmicron JMB381|
|Gigabit Ethernet||Broadcom BCM5784||Realtek 8111C|
|Audio Chipset||Realtek ALC888||Realtek ALC888GR|
|Special Features||Onboard SidePort Memory of 128MB (DDR3-1333)||