A790GXM-AD3 is the socket AM3 version from A790GXM-A, which we have already reviewed. It is an ATX-sized motherboard with on-board video based on AMD790GX chipset featuring two x16 PCI Express slots, HDMI output and other interesting features. Let’s take a look at this motherboard.

A790GXM-A, however, features a dedicated 128 MB on-board video memory in order to increase gaming performance (feature called “Side Port”), which is not present on A790GXM-AD3.

Right now AM790GX is the chipset with the fastest graphics engine available, called Radeon HD 3300. It is based on the same engine as AMD780G (Radeon HD 3200), but running at a higher clock rate (700 MHz vs. 500 MHz). It is also faster than the new AMD785G (Radeon HD 4200), which runs at the same clock rate as AMD780G (500 MHz). All these three chips have 40 processing units inside. AMD780G and AMD790GX are DirectX 10 parts, while AMD785G is DirectX 10.1. The second main difference between AMD785G and AMD780G/AMD790GX is the inclusion of more stages on the integrated video decoder and the inclusion of more stages on the chipset integrated video decoder (called UVD, Unified Video Decoder by AMD), which helps increasing performance when playing movies on your PC, since tasks that are traditionally performed by the CPU are now performed by the chipset. Another smaller difference is the support for HDMI version 1.3 on AMD 785G, while AMD780G and AMD790GX support HDMI 1.2.

AMD790GX is paired with SB750 south bridge chip, which provides two differences to SB700 (AMD780G) and SB710 (AMD785G). First the support for RAID 5. And the second, the support for ACC (Advanced Clock Calibration) that allows you to unlock hidden features from certain Phenom processors: depending on the CPU model you can unlock extra memory cache and even one extra CPU core, in the case of triple-core CPUs. You can read more about this feature here and here. So this feature is supported on this motherboard.

Keep in mind that socket AM3 motherboards are compatible only with socket AM3 CPUs. While socket AM3 CPUs can only be installed on socket AM2+ motherboards, you cannot install socket AM2+ CPUs on socket AM3 motherboards. In fact AMD says that this installation will burn the CPU and the warranty doesn’t cover this situation.

A790GXM-AD3 is part of Black Edition series from ECS, where one of the main features is using only solid capacitors. As mentioned it is an ATX motherboard, not microATX like the majority of motherboards with integrated video.

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Figure 1: ECS A790GXM-AD3 motherboard.