Introduction

Remember when ATI made crappy chipsets that no one bought, and all AMD systems were built with NVIDIA or even VIA chipsets? Yeah, that memory is fading for us too.

Today we get to officially unveil the 785G, the latest in integrated graphics chipsets by AMD for AMD. As the name implies, there is very little separating 785G from its predecessor (780G) and we’re quite ok with that. In fact, the only reason not to get a 780G is addressed by the 785: the new chipset supports 8-channel LPCM audio over HDMI. The lack of TrueHD and DTS-HD audio bit-streaming remains but neither is this feature supported on other chipsets. We also see a jump from HDMI 1.2 to 1.3 standards. Update: This story is developing in real time but AMD is telling us that 8-channel LPCM over HDMI is not supported in the final chipset. More info here.

The rest of the major improvements are strictly related to video playback duties. We jump from Universal Video Decoder (UVD) 1.0 on the 780G to UVD 2.0 capabilities on the 785G. The video decode engine supports decoding multiple HD streams (useful for picture-in-picture on a Blu-ray movie) and additional post processing effects if you are not a big video purist. Also new is the 785G's ability to perform detail enhancements on the fly.

The graphics side has not really changed that much. The new GPU is based off the RV620 core and is roughly the same size/complexity as the old one. In other words we get the same 55nm node process and almost the same amount of transistors, just a tad over 205 million.The 785G’s PowerPlay technology is improved with the core constantly adjusting clock speeds based on GPU utilization with a 60MHz target when idling compared to 500MHz at full load. AMD adds DirectX 10.1 support but stream processor count and clock speeds have not changed. Thus gaming performance remains mostly unchanged.

And in this corner: Intel

AMD is targeting Intel’s G41 with this 785G, and by simply by adding 8-channel LPCM and UVD 2.0 support it is no longer at a feature deficit for the HTPC audience. In fact, we cannot find one area where the 785G comes up short compared to the G41.

Intel’s G41 is a cost-reduced version of Intel’s G45 chipset. You lose PCIe 2.0 support (1.1 only) and integrated Gigabit Ethernet (only 10/100). Considering Intel recommends mating the ICH7 Southbridge to the G41 for cost purposes, you also lose RAID support, four USB ports, and two 3GB/s SATA ports compared to the AMD SB710.

  AMD 790GX AMD 785G AMD 780G Intel G45 Intel G41 NVIDIA GeForce 9300
CPU AMD Socket-AM2 AMD Socket-AM2 AMD Socket-AM2 Intel LGA-775 Intel LGA-775 Intel LGA-775
Manufacturing Process 55nm 55nm 55nm 65nm 65nm 65nm
FSB N/A N/A N/A 800 / 1066 / 1333MHz 800 / 1066 / 1333MHz 800 / 1066 / 1333MHz
Memory Controller N/A N/A N/A 2 x 64-bit DDR2/DDR3 channels 2 x 64-bit DDR2/DDR3 channels 2 x 64-bit DDR2/DDR3 channels
Memory Speeds Supported N/A N/A N/A DDR2-800/667
DDR3-1066/800
DDR2-800/667
DDR3-1066/800
DDR2-800/667
DDR3-1066/800
PCI Express 22 PCIe 2.0 lanes 22 PCIe 2.0 lanes 22 PCIe 2.0 lanes 16 PCIe 2.0 lanes 16 PCIe 1.1 lanes 20 PCIe 2.0 lanes
Graphics Radeon HD 3300 Radeon HD 4200 Radeon HD 3200 GMA X4500 GMA 4500 GeForce 9300 mGPU
Core Clock 700MHz 500MHz 500MHz 800MHz 800MHz 450MHz Core /
1.2GHz Shader
Shader Processors 8 (5-way) 8 (5-way) 8 (5-way) 10 10 16
Full H.264/VC-1/MPEG-2 HW Decode Yes Yes Yes Yes No Yes

The Radeon HD 4200 is where all the action is with this update but the more things change, the more they remain the same. We still have the traditional Northbridge/Southbridge layout with the NB supporting a 2GHz HyperTransport link compatible with the latest Socket AM3 processors. The 22 PCI Express 2.0 lanes are still around along with the four lane PCI Express 1.1 lanes supporting the A-Link Express connection between the two bridges.

The NB splits its 22 lanes between a single x16 link for graphics and six x1 links for expansion slots and onboard peripherals. Technically, the 785G chipset can't split its x16 graphics link into two x8 links for CrossFire X operation. The 785G supports hybrid CrossFire operation, but only with the older HD 3450/3470 video cards. We recommend skipping this feature, for now.

  AMD SB750 AMD SB700 Intel ICH10 Intel ICH7 NVIDIA GeForce 9300
Additional PCI Express None None 6 x1 PCIe 1.1 4 x1 PCIe 1.1 None
USB 12 ports 12 ports 12 ports 8 ports 12 ports
SATA (300MB/s) 6 ports 6 ports 6 ports 4 ports 6 ports
PATA 2 channels 2 channels None None 1 channel
RAID* RAID 0/1/5/10 RAID 0/1/10 RAID 0/1/5/10 None RAID 0/1/5/10
HD Audio Interface Yes Yes Yes Yes Yes
Ethernet Not Integrated Not Integrated Intel Gigabit LAN Intel 10/100 LAN (Gigabit through external controller) NVIDIA Gigabit LAN
Northbridge Interface 4 lane PCIe 1.1 4 lane PCIe 1.1 DMI 10Gb/s each direction, full duplex DMI 10Gb/s each direction, full duplex N/A, Single Chip Solution

The SB710 is essentially an updated SB700 with ACC (Advanced Clock Calibration) support, or looking at it a different way, a cost reduced SB750 without support for RAID 5 arrays. The SB710 has six 300MB/s Serial ATA ports with RAID 0, 1, and 0+1 support plus a single IDE port supporting two drives so JMicron and Marvell are held at bay on these systems. Twelve USB ports and a high-definition audio interface round out the SB710 as native GbE support is still missing.

It would have been nice to see next-gen USB and SATA support but that will have to wait for the SB8xxx updates next year. However, compared to the ICH7 mated with the G41, the SB710 is positively feature rich at the same price point.

We could continue on with subtle hints about why this chipset is a better alternative than the Intel G41 or its 780G/790GX siblings, but the bottom line is that AMD has taken an evolutionary step with this chipset, one for the better. That said, let's see how it performs against the other chipsets in its class.

Test Setup
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43 Comments

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  • MrCommunistGen - Tuesday, August 4, 2009 - link

    I was really curious about that section so I'm glad that I can actually view it. Thanks! Reply
  • fic2 - Tuesday, August 4, 2009 - link

    I find the choice of a 10k RPM VelociRaptor odd for either HTPC or integrated graphic system. I have my doubts that it would be the HD choice of either user profile. Reply
  • b15h09 - Friday, August 7, 2009 - link

    VelociRaptor because it eliminates a potential bottleneck. This isn't a real world system test. Reply
  • Taft12 - Tuesday, August 4, 2009 - link

    Yes, I would expect a WD Greenpower drive or one of those new slow-spinning Seagates. Reply
  • Fox5 - Tuesday, August 4, 2009 - link

    I remember roadmaps putting the 880G launching this month, but we're just getting the 785G. The 880G seems to be the chipset worth waiting for. Virtualized 3d hardware? Yes please. Reply
  • fzkl - Tuesday, August 4, 2009 - link

    A lot of us know that when it comes to an HTPC, Intel is the worst option of the lot. To make things fair, why isn't this a 3-way roundup with the Nvidia GeForce 9300? Reply
  • rtallmansu - Tuesday, August 4, 2009 - link

    Even more odd to me is why you would compare an Intel G41 with a ICH7 and not a G45 chipset with the newer ICH10. G41 buyers are not interested in any of these performance metrics, were as someone might want to know how the G45 compares for HTPC duties in HD playback. Reply
  • Shaffan - Tuesday, August 4, 2009 - link

    Such a pity you did not test the RAID performances : RAID5 in particular. I heard the integrated RAID5 of Intel chipset is much better than the one of AMD, but I can't find a decent comparative test about this ! Reply
  • flipmode - Tuesday, August 4, 2009 - link

    SB710 = no RAID 5 Reply
  • mybook4 - Tuesday, August 4, 2009 - link

    Gary, you put in a lot of effort into this article, thank you! However, I found one part misleading.

    Most of the application benchmarks are dependent on only cpu, not gpu. It confused me that these benchmarks were in an article that compared 780G vs G41. I understand if you were trying to compare the platforms as a whole, but wouldn't that also constitute a component price match (price an amd 780g system with an equal priced G41 system then compare).

    PS. I am a little sick of people saying that anything under 60fps is unplayable. Most people that frequent this site play Crysis at under 40fps.
    Reply

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