ASUS M4A785TD-V EVO and M4A785TD-M EVO AM3 Motherboards Review

AMD’s 785G/SB710 Chipset

Although there is plenty of information circulating on AMD’s 785G/SB710 since it’s release a few months ago, we thought we’d provide a quick overview and refresher for those interested. As always, we’ll start with the requisite block diagram.


Much like all AMD processors since the advent of the Athlon 64, memory control is exclusive to the processor and has virtually nothing to do with the chipset and platform. With that said, motherboard manufacturers can decide whether to offer DDR2 or DDR3 support as all AM3 processors are backward compatible with both standards. Both of the M4A785TD models we’re looking at today are exclusively DDR3, and we wouldn’t expect a lot of continued focus on DDR2 given the relatively similar price/GB for both DDR2 and DDR3 these days. We should also mention that although the 785G was released in tandem with the Athlon II series of processors, the platform equally supports higher end Phenom II processors. The only consideration that board makers must take into consideration is the higher TDP of Phenom II quads and must outfit power delivery systems accordingly. Both the EVO “M” and EVO “V” that we’re looking at today will accept all AM3 processors, including the 140W Phenom II X4 965.

The AM3 processor used on this platform interfaces with the 785G using the tried and true “HyperTransport 3.0” bus for heaps of bandwidth between processor and chipsets. As expected, all PCI-Express 2.0 lanes are provided by the 785G chipset for a grand total of 22 lanes. Only 16 lanes are provided for discrete video purposes and unfortunately, can’t be split for 8X/8X crossfire configurations as was possible with the 790GX. An additional six 1X lanes are available for either slots or for onboard components. Some motherboard makers set aside four of those lanes for CrossFireX support as we’ll see shortly with the M4A785TD-V EVO, but it is unfortunately a bandwidth-squeezed configuration for higher end cards.

Before we cover off on the new integrated Radeon 4200 IGP, let’s take a quick look at the SB710 southbridge. Without getting into too much detail, we’ll begin by saying that it is almost identical to the SB750. About the only real feature difference you’ll find is the lack of RAID-5 support – something almost no one in the consumer space is interested in. Six SATA-2 ports, a single Parallel ATA channel, twelve USB 2.0 ports, legacy PCI and HD Audio are all taken care of by the SB710. Another great feature that enthusiasts are very interested in that has been maintained in the SB710 is “Advanced Clock Calibration” or ACC. As we’ll see later in the review, the SB710 allows unlocking of Deneb cores just like it’s predecessor the SB750.

So with all of that out of the way, let’s take a closer look at the integrated Radeon 4200 graphics on the 785G.


Although newer than the 790GX, the 785G is not superior in performance. We just thought we’d get that out in the open right away. It is, however, superior to the older 780G in all respects. All three AMD IGPs platforms are built on the same low-power 55nm process and employ 40 shade-processors. The big thing that sets apart the 790GX from the 785G is clock speed. The 790GX operates at 700MHz compared to the 500MHz of both the 785G and 780G. Hopefully there will be some overclocking headroom on tap as we’ll test later in the review.

The significant differences really come in the form of features. The 785G is the first of the pack to bring DirectX 10.1 support, HDMI 1.3 and implementation of AMD’s UVD2. UVD2 or “Unified Video Decoder 2” brings further enhancement in the form of multiple video stream acceleration (think picture-in-picture) as well as other image quality enhancing features. Lots more information on UVD can be found here.

Like the 790GX, the 785G also supports “Hybrid Crossfire X”. This essentially allows the IGP core to work in tandem with a similar discrete graphics core to improve performance. There has surprisingly been a lot of confusion and contradictory information as far as which cards can be paired with the 785G. Given the 4000 series name, it seems odd that lower end 3000 series cards are intended to be paired with the chipset, rather than 4000 series cards. Even AMD’s hybrid crossfire site has not yet been updated to include the 785G at the time of writing. It sure would be nice to hear the official word from them on this.