Here is a short article I have made about the 790GX chipset for AMD processor based systems which targets the entry and mainstream user groups. It has been praised for it being a complete solution for a budget conscious buyer, combining an efficient and power conservative chipset with an on-board GPU which can have for the first time dedicated VRAM!
The 790GX Chipset
The chipset supports the socket AM2/AM2+ Sempron, Athlon, Phenom, the latest Phenom II and the forthcoming socket AM3 processors. HyperTransport 3.0 supported up to 2.6GHz.
Up to 4 DIMM modules are supported @ 1.066GHz DDR2 in dual channel mode.
Equipped with a full blown discrete Graphics solution supporting outputs through VGA, DVI (for Digital LCDs), HDMI, HDCP and the latest DisplayPort interfaces. The provision of Side Port memory enables the motherboard manufacturers to include dedicated VRAM on-board for the GPU.
CrossFireX and Hybrid CrossFireX support makes this board even richer in features.
Hybrid CrossFireX allows the on-board GPU to work together with any other discrete GPU installed in any of the PCIe slots.
Advanced Clock Calibration allows fine clock adjustments, allowing for greater overclocking margins!
Included with it, a full 7.1 surround sound audio chipset makes it a winner.
It also comes accompanied by the new revamped AMD Overdrive Utility, making overclocking easier for noobs and equally rich for professionals.
The 790GX consists of two components; the 790GX northbridge and an SB750 southbridge.
The 790GX Northbridge
The PCIe 2.0 configuration in 790GX is branched off into a pair of x8 links, offering the same 8 GB/s per slot you’d get from a first-generation x16 connection. The flexible PCIe configuration lets 790GX boast CrossFireX support for higher-end gaming. Also 790GX offers more than just a divisible PCIe link. The integrated RV610 core (Radeon HD 3300), armed with 40 stream processors, the same UVD support, and a 16-bit memory interface at 700 MHz.
Moreover, the side-port memory feature is now a standard feature on this chipset. Side-port memory is a DDR2/DDR3 cache that lives on the motherboard, directly connected to the graphics core. Without the memory, the RV610 core utilizes the HyperTransport interface to access DDR2 memory attached to the processor’s integrated controller. But by adding even just 128 MB of DDR3 running at 1.3 GHz, AMD claims performance jumps by as much as 15 percent.
Beyond the core’s 3D capabilities, it boasts the first-generation Avivo HD display pipeline, including AMD’s Universal Video Decoder. Even if you don’t install a discrete card, the integrated core’s UVD handles Blu-ray playback with ease. To that end, HDCP support is of course an important part of the package and, like AMD’s add-in boards, the Radeon HD 3300’s HDMI output does S/PDIF audio as well.
790GX offers two independent display controllers; one analog (VGA) and the other digital (dual-link DVI, HDMI, or DisplayPort). Given the scarcity of DisplayPort-equipped displays, expect most 790GX boards to include VGA, DVI, and HDMI outputs.
The northbridge also sports RAID 0, 1, 5 & 10 modes' support.
The SB750 Southbridge
790GX offers six additional lanes of PCI Express 2.0 connectivity that can be used by motherboard partners to integrate peripherals or enable expansion slots. AMD does not offer its own Gigabit Ethernet solution, so there’s one PCIe link that’ll almost certainly be populated on 790GX-based boards for the purpose.
The chip’s remaining four lanes of PCIe 2.0 constitute the connection between northbridge and southbridge. AMD brands the interface A-Link Xpress II, SB750 employs PCI Express 1.1, capping bandwidth at 2 GB/s.
Once you make your way past the pedestrian chip-to-chip interconnect, you’ll find that there’s a lot more to like about SB750. On the superficial surface, USB 2.0 support remains restricted to 12 ports (with two 1.1 ports thrown in as well), HD Audio persists, a single parallel ATA channel accommodates two IDE devices, and six SATA 3 Gb/s port accommodate plenty of storage.
But whereas SB700 was limited to RAID 0, 1, and 10 arrays across its six ports, SB750 adds RAID 5 functionality to its list of accolades.
More important than RAID 5, expansive USB connectivity, or missing Gigabit Ethernet, is a feature that AMD calls Advanced Clock Calibration, or ACC. There’s an aura of mystery shrouding what AAC actually does! What is known about ACC is that it’s a direct, low-level link between the southbridge and CPU that AMD says “functions to unlock a number of tumblers on the processor previously not accessible.” Beyond that, with the proper cooling configuration, AMD claims simply enabling ACC is enough to boost overclocking headroom by between 100 and 400 MHz.
The feature comes most highly recommended for owners of Black Edition CPUs — the ones who’ve likely hit a wall with simple multiplier and voltage increases. But it will also work with any Phenom processor you drop into the 790GX platform. Given AMD’s reluctance to sing the specifics of ACC, we’ll have to let testing do the talking on this one.
Some Motherboards From Renowned Vendors
MSI's DKA790GX Platinum