Introduction
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AMD is releasing today a new chipset with integrated graphics, AMD 890GX, and ECS has announced three socket AM3 motherboard models based on it. We are going to take a look at A890GXM-A, which belongs to ECS’ Black Series, featuring three PCI Express x16 slots and SATA-600 ports (but not USB 3.0 ports).
Before talking specifically about this motherboard from ECS, let’s briefly see what is new on AMD 890GX.
In the table below we provide a comparison between AMD 890GX and previous chipsets with integrated graphics from AMD: AMD 785G, AMD 790GX and AMD 780G.
As you can see, the main specs of the graphics engine from AMD 890GX is pretty similar to AMD 790GX’s, except that AMD 890GX uses a DirectX 10.1 engine while AMD 790GX’s is DirectX 10.
The main difference on AMD 890GX is the use of a new south bridge chip, called SB850. This south bridge chip natively supports SATA-600 ports (a.k.a. “SATA 6 G”) and in fact this is the first chipset to arrived on the market with this feature (currently on motherboards based on other chipsets featuring SATA-600 ports an external controller chip must be used). Like the SB750 used with AMD 790GX, they support RAID level 5, a configuration not supported on SB710 and SB700.
Notice how SB850 supports only USB 2.0 ports. There are some motherboards based on this chipset that have USB 3.0 ports, but they are controlled by an external chip.
| Chipset | AMD 890GX | AMD 785G | AMD 780G | AMD 790GX |
| GPU Clock | 700 MHz | 500 MHz | 500 MHz | 700 MHz |
| Graphics Processors | 40 | 40 | 40 | 40 |
| ROPs | 4 | 4 | 4 | 4 |
| Engine | HD 4290 | HD 4200 | HD 3200 | HD 3300 |
| DirectX | 10.1 | 10.1 | 10 | 10 |
| PCI Express | 2.0 | 2.0 | 2.0 | 2.0 |
| South Bridge Chip | SB850 | SB710 | SB700 | SB750 |
| USB 2.0 Ports | 14 | 12 | 12 | 12 |
| SATA-300 Ports | None | 6 | 6 | 6 |
| SATA-600 Ports | 6 | None | None | None |
| RAID | 0, 1, 5, 10 | 0, 1, 10 | 0, 1, 10 | 0, 1, 5, 10 |
| ATA-133 Ports | 1 (2 devices) | 1 (2 devices) | 1 (2 devices) | 1 (2 devices) |
ROPs stand for “Raster Operation Units” and are also known as “Rendering Back-End Units.” They are the final stage on rendering a 3D image.
Other chipsets with on-board video from AMD include AMD 690V, AMD 690G, AMD 740G and AMD 780V. AMD 690V, AMD 690G and AMD 740G are based on a DirectX 9 graphics engine, while AMD 780V is based on a DirectX 10 one. AMD 780V is based on Radeon HD 3100 engine, which runs at 400 MHz – clock is the main difference between HD 3100, HD 3200 and HD 3300 engines.
Like SB750, SB850 south bridge chip supports an overclocking feature called “Advanced Clock Calibration” or simply ACC. How exactly this new feature works is completely obscure, as AMD does not explain how it works in details. All we know is that SB850 provides a feedback loop to Phenom/Phenom II processors using some unused CPU pins, allowing you to unlock hidden features from the CPU – most commonly unlocking an extra CPU core on triple-core CPUs. You can read more about this feature here and here.
As you may know by now, on systems with integrated video the video memory is achieved by stealing part of the main RAM. Chipsets from AMD have a feature called SidePort, which is an optional memory chip soldered on the motherboard in order to increase video memory. This motherboard from ECS brings this feature, having 128 MB of GDDR3-1600 memory on-board to speed up video.
In Figure 1, you can see the basic block diagram from AMD 890GX chipset.
Figure 1: AMD 890GX chipset.