Summary: With DirectX 10.1 graphics, UVD 2, and support for GPU-based video transcoding, AMD's 785G chipset with Radeon HD 4200 graphics promises to usher in a new era of features and performance for the consumer on a budget, but can it run Crysis? See how AMD's latest IGP compares to Intel in this article!
Each month Intel ships tens of millions of G45, G43, G41, GMA X4500, GMA X3100 and older integrated graphics chipsets to customers around the world. These IGPs (integrated graphics processors) are then sold in the $300 and $400 desktop and notebook PCs found from computer manufacturers like HP and Dell.
AMD wants in on more of this action. Seeing the huge volumes of IGPs Intel moves each month, who can blame them? When they purchased ATI back in 2006 they cited the fusion of the CPU and GPU as one of the keys to the purchase, but in the short term they also hoped that ATI's chipsets and IGPs would help them score new design wins with OEMs leery of purchasing CPUs from one source and IGPs from another (usually NVIDIA), and ultimately help them take some share from Intel.
Unfortunately for AMD, despite a good product lineup, things haven't quite panned out as originally planned.
Intel was actually first to market with an IGP that supported DirectX 10 graphics. Their Bearlake series of G3x chipsets beat AMD to the punch by several months, scoring the design wins AMD had hoped for despite the fact that AMD's first DX10 offering, the 780G chipset, delivered better 3D graphics performance than Intel G35.
780G was a pretty remarkable chipset for its time. Thanks to a die shrink, ATI was essentially able to integrate their existing RV620 GPU found in their Radeon 3450/3470 value cards and put it in the 780G chipset itself. ATI had to knock the clock speeds down a little in order to fit within their power/thermal budget, but other than that, it was basically the same GPU.
Hybrid Graphics was the feature that really put 780G on the map though. Like ATI's CrossFire technology, with Hybrid Graphics, you could pair a discrete Radeon 3450 graphics card with the graphics core integrated in the IGP for a nearly 2X performance increase in games. It was the first time mutli-GPU technology was found in an IGP from any manufacturer (NVIDIA followed with their own solution later).
Now ATI and AMD are back with their successor to 780G. Internally dubbed 785G, to the outside world AMD will market it as the Radeon HD 4200 or 785G chipset with Radeon HD 4200 graphics. The Radeon HD 4200 nomenclature suggests this is a new part based on an RV7xx derived Radeon 4000 graphics core, but the 785G designation implies this chipset is an incremental improvement over the 780G platform. Which one is it? Let's find out!
Fundamentally the architecture of the graphics core itself is pretty similar to the GPU found in the 780G's Radeon 3200 graphics. You've got the same 40 stream processors with 4 texture units and 4 ROPs as the 780G, the same ability to address up to 512MB of system RAM, and the same 500MHz core clock speed.
This is probably a disappointment for those of you who were hoping for a true next-generation successor based on ATI's highly successful RV7xx architecture. The Radeon HD 4350 for instance sports twice the stream processors -- 80 -- with eight texture units and 4 ROPs. With the 785G chipset relying on the same 55-nm manufacturing process as the 780G, ATI couldn't affordably fit the 4350's 242 million transistors into their transistor budget for 785G.
As such, 785G's Hybrid Graphics support is limited to the Radeon 3400 series, just like its predecessor the 780G.
Hybrid Graphics isn't going to be a big selling point this time around though. Finding Radeon 3400 cards is becoming increasingly difficult. Newegg for instance only lists three Radeon 3450 boards in stock right now, and two of them are priced higher than the Radeon 4350. Not that it would matter anyway, as one Radeon HD 4350 graphics card is going to run faster than the 780G+Radeon 3450 Hybrid Graphics combination. Radeon 4350 cards start for just $3 more than the cheapest 3450 card on Newegg.
We ran benches with the 785G's integrated graphics and discrete Radeon 4350 graphics card benchmarks for this article so you can see how the two graphics solutions fare against each other.
ATI has added a few new ingredients to the 785G IGP that aren't found in 780G though. For starters, the chip now fully supports DirectX 10.1, whereas 780G was limited to supporting DirectX 10.0. DirectX 10.1 is a pretty incremental improvement over DirectX 10 though, and considering that IGPs don't have the graphics processing horsepower to run DX10 titles anyway it's probably more of a check mark feature for OEMs than anything else.
More notable additions ATI has incorporated into the 785G chipset include HDMI 1.3 support (780G was limited to HDMI 1.2), and RV7xx features like support for hardware video transcoding on the GPU rather than the CPU utilizing ATI Stream, and ATI's Unified Video Decoder 2 (UVD 2); both of these features were first introduced with the Radeon 4000 series of GPUs last year. 785G can also output multi-channel LPCM audio over HDMI as well.
UPDATE 8/5/09: AMD confirmed that multi-channel LPCM audio over HDMI isn't supported by 785G; like 780G the 785G chipset is limited to 2 channels only.
If you recall, UVD 2 includes support for hardware-accelerated picture-in-picture for watching Blu-ray movies, and video enhancement features like dynamic contrast, HD color enhancement (including flesh tones and color vibrance), and post-processing effects like noise reduction, de-interlacing and HD pulldown detection, which is only supported when dynamic contrast is turned off.
So essentially with 785G you could say ATI's fusing the graphics horsepower of RV620 with the video capabilities of RV730. That description isn't completely accurate, but it gives you a quick synopsis of how the new IGP differs from previous ATI offerings. The South Bridge carries over unchanged, with AMD's SB7xx series of chips supported. This is the same chip already in use on current 7-series platforms.
To test the capabilities of the 785G platform out we've got two motherboards from ASUS and Gigabyte. The ASUS board is their M4A785TD-M EVO, while the Gigabyte motherboard used for testing is an engineering sample GA-MA785GPMT-UD2H. We normally don't like to test engineering sample motherboards, preferring to stick with retail samples instead, so instead we'll provide an overview of the product and its current feature set and BIOS. We'll save the more detailed analysis with performance for when we get our hands on a retail sample.
The feature set of both 785G boards we have here in house are eerily similar. They both feature the same number of ports, expansion slots, display outputs, and I/O as each other. For added IGP performance, they both also ship with 128MB of DDR3 Sideport memory. It's almost as if ASUS and Gigabyte had a copy of each others playbook for 785G. We'll go in ABC order though, starting with ASUS.
ASUS M4A785TD-M EVO
The ASUS M4A785TD-M EVO is one of the first ASUS motherboards to sport a PCB that uses 2-ounces of copper for the power and ground layers of the board, just like Gigabyte. This is a move designed to reduce the operating temperature of the motherboard, which in turns help to reduce the temps of the board's underlying components.
As you can see in the pictures, the M4A785TD-M EVO features one x16 PCIe graphics slot and one x1 PCIe slot. For additional expansion, ASUS also includes two PCI slots.
Out back you'll find HDMI, DVI, and VGA video outputs along with 6 USBs, 1 eSATA, and 1 Firewire port.
The BIOS ASUS provides for the M4A785TD-M EVO is quite good for a micro-ATX solution. For overclocking, HyperTransport speeds ranging from 200-550MHz are available in 1MHz increments. Clock multipliers range from 8.0 up to 35.0, with half multipliers in between. As a result, you could theoretically dial up clock speeds up to 7GHz if you had a processor capable of hitting such high speeds.
GPU Overclocking is also supported, so you can OC the Radeon HD 4200 IGP for added performance. Speeds range from 500-1500MHz in 1MHz increments (we managed to hit speeds up to 780MHz on the IGP with complete stability). PCIe speed adjustments range from 100-150MHz in 1MHz increments, while memory multipliers are available in BIOS for DDR3 speeds up to 1600MHz.
Voltage adjustment is also supported. CPU voltages range from 0.975V-1.7V in increments of 0.00625V. Voltage settings for HyperTransport (1.25-1.385V in 0.01500V increments), North Bridge (0.8-1.55V in 0.00625V increments), DDR3 memory (1.5-2.31V in 0.015V increments), and South Bridge voltage (1.1-1.61V in 0.0150V increments) are also available.
For those of you with dual or triple-core CPUs, the board's BIOS also offers the ability to unlock all the processing cores on your CPU, effectively giving you a quad-core part, but keep in mind that not all processors will function properly once all four cores are unlocked: none of the dual or triple core processors we have here in the labs works with this feature.
Overall the ASUS M4A785TD-M EVO should offer more than enough features for DIY'ers looking for a low-cost 785G solution. Its flexible BIOS should also allow plenty of room for enthusiasts to push the limits when OC'ing.
The board should appeal to HTPC users, the SFF crowd, and budget gamers alike. Like the ASUS board, the GA-MA785GPMT-UD2H features DVI, VGA, and HDMI video outputs all on the backplane of the motherboard. Six USB ports can also be found on the backplane in addition to eSATA, Firewire, audio and optical outs. For expansion, the board sports one x16 PCIe graphics slot and one x1 PCIe slot as well as two PCI slots, in addition to four DIMMs.
Audio duties are handled by Realtek's ALC889A CODEC, which is a pretty popular 7.1 high definition audio solution among motherboard manufacturers. The 889A chip supports DTS Connect and boasts a 106dB signal-to-noise ratio. Realtek's RTL8111C GigE networking controller handles comms.
The layout of the board is pretty similar to Gigabyte's 780G motherboard, the GA-MA78GM-S2H. All the key components are located in the same areas, only the newer GA-MA785GPMT-UD2H has a beefier power subsystem with better chipset cooling. Gigabyte's 780G board didn't feature all-solid capacitors either. The newer 785G board is definitely the better board in terms of those components.
The GA-MA785GPMT-UD2H sports a feature complete BIOS as well. Like the ASUS motherboard, you can OC the CPU to your hearts content, as well as the Radeon HD 4200 IGP graphics. HyperTransport speeds range from 200-500MHz in 1MHz increments while IGP speeds from 200-2000MHz are available if you'd like to overclock the integrated GPU. PCIe speeds range from 100-200MHz, also in 1MHz increments.
For OC'ing Black Edition processors, clock multipliers range from 5-35.0x, just like the ASUS motherboard. Both boards feature the same DDR3 memory multipliers as well, with Gigabyte offering multiplier options of 4.0x, 5.33x, 6.66x, and 8.0x (1600MHz).
In terms of voltages, Gigabyte provides settings for undervolting or overvolting the component in question to whatever setting you'd like. For the CPU for instance you can run voltages as high as 0.60V over the stock CPU voltage, or you can undervolt the CPU up to 0.60V under the stock CPU voltage. For a 1.3V CPU, this could be up to 1.9V, or just 0.7V of juice. Overvoltage options are also available for the North Bridge (+0.1V, +0.2V, +0.3V) South Bridge (+0.1V, +0.2V, +0.3V), CPU North Bridge VID (+0.025V-+0.600V in 0.025V increments), DDR3 voltage (+0.05V-+0.750V in 0.05V increments), and Sideport memory voltage (+0.1V, +0.2V, +0.3V).
Like the ASUS M4A785TD-M EVO, the GA-MA785GPMT-UD2H BIOS also supports unlocking the fourth core for triple-core and dual-core Phenom II CPUs.
AMD Athlon II X2 250
Intel G41 Testbed
Intel Pentium E6300
Call of Duty 4
Valve Particle Simulation Benchmark
Fallout 3 Direct3D
Call of Duty 4 – DirectX 9
Crysis – DirectX 10
Far Cry 2 – DirectX 10
The addition of ATI Stream support brings hardware video transcoding to the IGP for the very first time. UVD 2 also brings with it numerous video enhancement effects like dynamic contrast and noise reduction, while HDMI 1.3 and support for multi-channel LPCM audio output are great new features for the HTPC user as well.
All of these features should make the 785G chipset a popular choice among the home theater/SFF crowd.
The gamer in us though is a bit disappointed in the evolutionary nature side of the 3D graphics engine. The 3D core of the IGP now supports DX10.1, but lets be honest, the Radeon HD 4200 graphics core isn't up to the task of running a DX10 game like Far Cry 2 or Crysis in DX10. For both of these games you're going to need to run the game in DX9 mode at 800x600 or 1024x768 with low detail graphics settings to get acceptable frame rates.
In AMD's defense though, at least 785G is capable of dishing out acceptable gaming performance. Its closest competitor in terms of price, Intel's G41 chipset, was woefully inadequate at keeping up with the 785G in our benchmarks. Generally 785G ran twice as fast as G41 in most of our tests, sometimes the margins were even worse. In Crysis for instance the 785G chipset ran around 29 fps at 1024x768; in comparison the G41 chipset chugged along at around 9 fps. Fallout 3 with medium graphics settings couldn't even run without crashing at some point on G41!
Only in Call of Duty 4 was Intel's G41 IGP somewhat competitive with 785G in gaming performance. Even in this rosiest of scenarios for Intel, G41 was still behind by a very noticeable 29%.
Clearly AMD's 785G chipset is the better all-round solution in comparison to Intel's G41 IGP.
Our benchmarks also favored the AMD platform as a whole over Intel. When our 785G and G41 testbeds were equipped with an ATI Radeon HD 4350 discrete graphics card, the AMD platform outran Intel thanks to the superior performance of the Athlon II X2 250 CPU. The Pentium E6300 is the better OC'er, but at stock speeds the Athlon II 250 appears to be the better performing processor for gaming with the Radeon 4350.
So AMD didn't push the bar any further when it comes to gaming. Clearly based on our performance results though, they didn't need to. They did address most of the video features HTPC users have been asking for, and they pushed the bar a little further thanks to ATI Stream.
If we were building a low-cost $300 PC for general purpose use that's equally adept at gaming, HTPC use, and basic Windows duties, the 785G with Athlon II would definitely be our starting platform of choice. Once your budget allows, you could then upgrade to a more powerful Radeon 4670, which would allow you to crank up the in-game graphics settings considerably, maybe even throw in up to 2xAA. Or you could really step up and get a Radeon 4850 or GeForce GTX 200 series card.
With motherboard prices ranging from $80-$100, 785G is the low-cost integrated platform of choice right now though. The competition isn't that close in this price range either.
Great job AMD, call us when you can figure out a way to squeeze the Radeon 4350 in your next IGP. We'll likely have to wait for 40-nm for that to happen though.
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