Updated: AMD 785G: The Venerable 780G, Evolved

Radeon HD 4200 Enhancements

For years now, we've wished that someone would come out with an IGP capable of handling today's games at reasonable detail settings and at resolutions of at least 1280x1024, which is the lowest resolution at which I'd be happy playing.

The Radeon HD 4200 built into AMD's 785G chipset is, unfortunately, not the realization of this dream.

Don't get me wrong. The 785G is a great IGP, but it's pretty much exactly as great as the 780G before it, as the performance-oriented specifications have remained essentially identical: 40 stream processors, four texture units, and four ROPs. The 785G even runs at the same clock speed as the 780G, 500 MHz.

So what's different abut the 785G graphics processor? DirectX 10.1 support is the obvious answer. And, well, not much more as far as hardware specifications go:

AMD 78x and 79x Graphics Processors

AMD 785G AMD 780G AMD 790GX
Integrated Core RV620 RV610 RV610
DirectX/OpenGL 10.1/2.1 10.0/2.1 10.0/2.0
Shaders/TU/ROP
40/4/4
40/4/440/4/4
Graphics Clock 500 MHz 500 MHz 700 MHz

As suggested by the name 785G, this is an incremental upgrade. The DirectX 10.1 enhancements will not offer any immediate performance benefits for the end-user. DirectX 10.1 features can be enabled, but these won't likely speed up the frame rates, as we will demonstrate in our game benchmarks.

While the chipset's 785G designation reflects minor improvements, the name of the Radeon HD 4200’s GPU is quite a bit more provocative. Given its name, one might assume that the Radeon HD 4200 (785G) is superior to the Radeon HD 3300 (790GX), which is not the case when it comes to gaming. The 790GX is clocked at 700 MHz, while the 785G is clocked at 500 MHz. And with everything else being pretty much equal, the 790GX is, of course, notably faster.

The bottom line is that the AMD 790GX and Nvidia GeForce 9400 remain the fastest gaming IGPs out there. As for the good news, most 780G or 785G chipsets should be able to overclock to 790GX specifications or a little higher without cooling modifications, so the end-user can experience passable 1024x768 gaming performance with a little tweaking. This is fine for the casual gamer, but discrete graphics remains the only solution for more demanding settings.

Things might get interesting in the next generation of IGPs if AMD integrates something similar to the Radeon 4350 with its 80 shader processors into a chipset, but I suspect we might not see that for a while yet, as it'll likely require a manufacturing shrink. And when that happens, the day's games will be more demanding and the cycle of pain will continue.

Note that some 785G-based boards will have an advantage over early 780G platforms, because they seem more likely to sport SidePort memory. The cache, consisting of 128 MB of DDR3, serves as dedicated video RAM for the IGP, boosting performance slightly. While some 780G motherboards do offer SidePort memory, it's much more common on the 790GX chipset.

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  • macer1
    the real question is how would this perform if mated to an Atom processor in an nettop.
    -23
  • mcnuggetofdeath
    "refined architecture" ? To my knowledge, and please correct me if im wrong, all that was changed between the original phenom and the phenom 2 was the addition of more L3 cache allowing it to do more simultaneously and a die shrink allowing for higher clocks. That does not a refined architecture make. When AMD added an on die memory controller to their processors years ago they had made a huge advancement in architecture. Im sad to see them fall away from the performance crown. Here's hoping their new Bull Dozer architecture brings something genuinely intriguing to the table.
    -10
  • mcnuggetofdeath
    ^^^ and support for DDR3. Although thats a change to the board, not the CPU.
    -18
  • anamaniac
    Very interesting.
    A integrated GPU that can game. =D

    Makes my lil Pentium D with a 4670 seem puny...
    3.3GB/s memory bandwidth (single channel DDR2 533... though 2 sticks, it runs in single channel... damn prebuilts) also seems sad on my rig...

    macer1the real question is how would this perform if mated to an Atom processor in an nettop.


    Good question. A dual core Atom with a 4200 integrated would be nice.
    We all know Intel makes shitty mothebroards and AMD makes kickass motherboards anyways.
    -3
  • SpadeM
    mcnuggetofdeath^^^ and support for DDR3. Although thats a change to the board, not the CPU.


    Not correct, the P2 has a built in memory controller so the switch to ddr3 affected that controller
    9
  • apache_lives
    anamaniacVery interesting.A integrated GPU that can game. =DMakes my lil Pentium D with a 4670 seem puny...3.3GB/s memory bandwidth (single channel DDR2 533... though 2 sticks, it runs in single channel... damn prebuilts) also seems sad on my rig...Good question. A dual core Atom with a 4200 integrated would be nice.We all know Intel makes shitty mothebroards and AMD makes kickass motherboards anyways.



    Native ram for a pentium d is PC4200 which has a max of 4.2gb/s per channel etc and the FSB has the max of 6.4gb/s

    The Intel atom would most likely underpower any video card out there, and Intel does actually make a good reliable business platform where video performance is not required etc
    1
  • Anonymous
    I'm sorry, is this an Intel benchmark site? All other reviews put SYSTEM power consumption for Athlon II 250 well below Intel E7200.
    -3
  • aproldcuk
    This article raised a lot of questions for me. What about Hybrid Crossfire for example? What kind of cards can be used together with this new IGP? Is the discrete graphics card on standby if no performance is required? If no then how much extra outlet wattage is expected? And how much extra if actively in use? I'm interested in using the 785G solution in the 24/7 HTPC setup with the possibility to do occasional gaming as well. My current setup with 690G chipset and Athlon 64 X2 BE-2350 CPU draws around 50 watts most of the time and up to 90 watts under heavy load. Is it too much to expect similar levels from 785G and Phenom II X3 705e combo for example?
    1
  • wh3resmycar
    when can we see the mobile version of this? this is most certainly a welcome update compared to the 780g-hd3200 chipset. and beats any nvidia igp hands down. id love to see this on an $700-$800 laptop. good thing im still holding back on buying a new notebook.
    1
  • Pei-chen
    Good timimg, I was wondering if 785G is better than 790GX or not yesterday. Thanks.
    4
  • neiroatopelcc
    ArticleThere are two lessons to be learned here: first, if you really care about the environment, turn your PC off (or at least configure it to enter sleep mode) when you're not using it, and second, don't be afraid of purchasing a better processor for fear that it will cost you big money in power consumption.


    Perhaps the next task could be a power comparison to tell us how long a computer needs to stand in active state to consume more power than turning it off and back on again (including starting msn,av software and a bunch of other stuff running in the background).

    Anyway good article :)
    0
  • Anonymous
    McNuggetOfDeath: There were changes to the Phenom II architecture, 45nm is not what enabled higher clocks, it was architectural changes(mostly regarding internal latencies). There were also other changes as well that enabled higher IPC and smoother overall performance.

    PS: Phenom II does support DDR3, there are only 2 models out of 12 that don't...
    3
  • Onus
    Pei-chenGood timimg, I was wondering if 785G is better than 790GX or not yesterday. Thanks.

    ========
    My take on it is except for some specific HTPC features, the 790GX is still the better of the two, especially if any gaming is involved. They compared an OC'ed 785G to a stock 790GX; what if they'd OC'ed the 790GX also?
    And, lest anyone develop any false hope, the Intel IGP has once again been shown to be a toad.
    2
  • DarkMantle
    One of the best things this chipset brings is a lower cost on AM3 motherboards, if you want to use PhenomII processors paired with DDR3 ram and a single video card, you can pay 89-99 dollars for the motherboard. I think this is important.
    8
  • judeh101
    I would totally use this with my home theatre PC.
    Let's seee... Decent performance, able to play HD videos, low cost. That covers everything I need for a HTPC!
    7
  • cleeve
    aproldcukThis article raised a lot of questions for me. What about Hybrid Crossfire for example? What kind of cards can be used together with this new IGP?


    We concentrated on the new aspects of the 785G in this article; hybrid crossfire is exactly the same as it was with the 780G, that is to say it maxes out with a 3450 card.
    2
  • Ryun
    "At idle, the Phenom II X2 is drawing the highest load: 92 W on the 790GX motherboard. In contrast, the E7200 is drawing 68 W on the most efficient platform, Intel's G45. It looks big on the chart, but it's a difference of 14 W."

    Nope, it's using a 24 W difference. I think that's why your numbers are different too. I get:

    24 Watts * 24 hours = 576 WHrs / 1000 W/KW = .576 KWHrs * $0.15 cents/KWHr * 365 days = $31.54

    Good article otherwise, thanks.
    4
  • Anonymous
    Quote:
    refined architecture" ? To my knowledge, and please correct me if im wrong, all that was changed between the original phenom and the phenom 2 was the addition of more L3 cache allowing it to do more simultaneously and a die shrink allowing for higher clocks. That does not a refined architecture make. When AMD added an on die memory controller to their processors years ago they had made a huge advancement in architecture. Im sad to see them fall away from the performance crown. Here's hoping their new Bull Dozer architecture brings something genuinely intriguing to the table.


    That is incorrect, if that was the case, the Phenom II wouldn't benchmark so much better and it wouldn't overclock so much better. Just because it has the Phenom name to it, doesn't mean all they did was give it a bit more L3 Cache and call it a day. You could've given the original Phenom more L3 cache all day long and it wouldn't still ran like poop. Not necessarily poop, but just not as well as the Phenom II.
    -1
  • KT_WASP
    cleeveWe concentrated on the new aspects of the 785G in this article; hybrid crossfire is exactly the same as it was with the 780G, that is to say it maxes out with a 3450 card.


    If this is true, then why does the Hybrid crossfire graphic on the first page show HD4350, HD4550 and HD4650 as compatible hybrid crossfire GPUs?

    It makes sense.. the 780G used an integrated 3200-series GPU, so it was compatible with lower-end dedicated 3000-series GPUs. The 785G uses an integrated 4200-series GPU, so it should be compatible with the lower-end dedicated 4000-series GPUs.

    Can you clear this up? I was also wondering what GPU's can be used as Hybrid crossfire with the 785G. I thought I knew from that graphic on page 1, but your response confused me.

    Thanks
    4
  • aproldcuk
    cleevehybrid crossfire is exactly the same as it was with the 780G, that is to say it maxes out with a 3450 card.

    Thanks for clearing it out, Cleeve! There is not much sense using Hybrid CF then. However, my original question still remains: how much extra wattage may one expect with mid-range 4600 or 4700 card added for example? Does disabling the device help here a bit more when not in use? Hope this is not too off-topic already...
    1