If you've been on top of the PC scene for any length of time, you probably know that whether by choice or necessity, AMD has taken a different tact as of late. Whereas the company was all about bigger, faster, and better during the Athlon's heyday, AMD is now more about touting the performance per dollar and value of their products.  While they may not have a CPU with the horsepower to compete in the benchmark war with Intel's $1000 behemoths, AMD's affordably priced Phenoms do offer good bang for the buck.

The value conscious mentality that has permeated AMD's recent graphics card and processor launches has also rung true in their motherboard chipset business as well. The 690G and 780G, for example, offered solid feature sets and excellent IGPs, at very affordable prices. And today, AMD continues their recent traditions with the introduction of the 790GX chipset.

The AMD 790GX is a tough product to categorize. It is targeted at value conscious gamers, enthusiasts, and multimedia buffs all at the same time. The block diagram above gives a high-level overview of the chipsets main features and illustrates how each component is connected in the architecture.

As you can see, the AMD 790GX Northbridge is connected to the AM2+ socket through a HyperTransport 3.0 link and it sports and integrated graphics core, along with a flexible PCI Express lane configuration. PATA, 6 SATA ports, HD audio, and 12 USB ports are supported by the SB750 Southbridge.  Also, at the bottom of the diagram, a new feature you may not be familiar with, makes its debut--ACC, or Advanced Clock Calibration. More of ACC a bit later.

790GX Northbridge

The AMD 790GX is manufactured at 55nm and features an Integrated Radeon HD 3300 Graphics Processor (IGP) that integrates a DirectX10 compliant Shader Model 4.0 graphics core, a Unified Video Decoder (UVD), two x8 PCI Express 2.0 links or 1 x16 link, HyperTransport 3.0, DVI / HDMI interface, and internal / external TMDS and DisplayPort capability in a single chip. The graphics core is actually identical to the one found in the 780G, but in the 790GX, it is clocked much higher (700MHz) for up to 33% better performance, PowerPlay features have been enahnced to support lower power states, and many boards featuring the 790GX will be equipped with dedicated sideport memory, for increased performance. Of course, the 790GX supports ATI Hybrid CrossFire technology as well, for increased performance or low-power operation.

SB750 Southbridge

The AMD SB750 Southbridge communicates with the Northbridge through the A-Link Express II interface.  The AMD SB750 offers support for both SATA RAID and IDE drives and it is the key piece in the Advanced Clock Calibration puzzle.  In total, the SB750 supports 6x SATA 3.0 Gb/s ports that can be setup in IDE, AHCI, JBOD, RAID 0, RAID 1, RAID 5 or RAID 10 modes, 12x USB 2.0 and 2x USB 1.1 ports, DASH 1.0, 6x PCI slots, HD Audio, IDE, and Serial and Parallel ports.

To evaluate the new AMD 790GX chipset, we got out hands on a retail ready motherboard from Gigabyte, the MA790GP-DS4H.

The Gigabyte MA790GP-DS4H exposed all of the features inherent to the 790GX and adds many more through the use of additional on-board controllers.  As you can see, the board is passively cooled by an array of copper heatsinks linked together via a pair of copper heatpipes, and is this completely silent.  During testing, we found the heatsinks to get just warm to the touch so heat should not be an issue here.

The board is outfitted with three PCI Express x1 slots, two x16 PEG slot (with x8 electrical connections) and two standard PCI slots.  All of its main connectors and headers are situated around the edges of the board, save for a band of four USB headers, located just behind the third x1 slot.  The board’s headers are clearly marked, labeled, and color coded, which made working with the MA790GP-DS4H a breeze during setup.  Overall we found the layout to be good.

In the MA790GP-DS4H’s external I/O port cluster, you’ll find PS/2 mouse and keyboard ports, VGA, DVI, and HDMI display outputs (any two can be used simultaneoudly with only the IGP), four USB ports, analog and digital HD audio outputs, a Gigabit LAN port, and finally a Firewire port. The board’s audio comes by way of a Realtek ALC889A 8-Channel HD codec, Firewire by way of a TI controller, and Gigabit LAN duties are handled by a Realtek RLT8111 chip.

We should also note, that the MA790GP-DS4H's integrated Radeon HD 3300 IGP is backed by 128MB of 1333MHz dedicated frame buffer memory. Having dedicated frame buffer memory (dubbed sideport memory), makes the IGP essentially act like a discreet graphics card because system memory will be used less frequently. The combination of the higher clocked graphics core and dedicated sideport memory are what make the 790GX a better performer than the 780G, and what arguably make it the best IGP on the market today, in terms of both features and performance.

One of the 790GX's more interesting features comes by way of the SB750 Southbridge. Dubbed ACC, short for Advanced Clock Calibration, the feature is designed to enhance the overclocking potential of Phenom processors. AMD hasn't revealed exactly how the technology works, but its name and the fact that the Southbridge now has a dedicated link to the CPU, speaks to ACC's ability to keep clock frequencies in sync and stabilize inter-chip communications between the CPU, Northbridge, Southbridge and memory.

AMD Phenom 9850 Overclocked to 3.1GHz

How We Configured Our Test Systems: When configuring our test systems for this article, we first entered their respective system BIOSes and set each board to its "Optimized" or "High performance Defaults". We then saved the settings, re-entered the BIOS and set memory timings for either DDR2-1066 (AMD) with 5,5,5,15 timings or DDR3-1333 with 7,7,7,20 timings (Intel). The hard drives were then formatted, and Windows Vista Ultimate was installed. When the Windows installation was complete, we updated the OS, and installed the drivers necessary for our components. Auto-Updating and Windows Defender were then disabled and we installed all of our benchmarking software, defragged the hard drives, and ran all of the tests.

HotHardware's Test Systems  Intel and AMD - Head To Head

System 1: Core 2 Quad Q6600 (2.40GHz - Quad-Core) Core 2 Quad Q9650 (3.0GHz - Dual-Core)  Asus P5E3 Premium (X48 Chipset) Intel G45PID (G45 Express) 2x1GB Corsair DDR3-1800 CL 7-7-7-20 - DDR3-1333 GeForce 8800 GTX On-Board Ethernet On-board Audio WD740 "Raptor" HD 10,000 RPM SATA Windows Vista Ultimate DirectX Redist (June 2008)

System 2: AMD Phenom X4 9850 (2.5GHz) Asus M3N-HT Deluxe (nForce 780a SLI) Gigabyte GA-MA790GP-DDS4H (AMD 790FX Chipset) 2x1GB Corsair PC2-8500 CL 5-5-5-15 - DDR2-1066 On-Board Ethernet On-board Audio WD740 "Raptor" HD 10,000 RPM SATA Windows Vista Ultimate DirectX Redist (June 2008)

Preliminary Testing with SiSoft SANDRA XII  Synthetic Benchmarks

We began our testing with SiSoftware's SANDRA XII, the System ANalyzer, Diagnostic and Reporting Assistant. We ran three of the built-in subsystem tests that partially comprise the SANDRA XII suite with an AMD Phenom X4 9850 processor installed in the Gigabyte MA790GP-DS4H motherboard (CPU Arithmetic, Multimedia, and Memory Bandwidth).  All of the scores reported below were taken with the processors running a clock speed of 2.5GHz, with 2GB of DDR2-1066 RAM installed.

Phenom X4 9850 @ 2.5GHz CPU Arithmetic	Phenom X4 9850 @ 2.5GHz Memory Bandwidth	Phenom X4 9850 @ 2.5GHz Memory Latency

Our Phenom X4 9850 processor performed as expected in the three SiSoft SANDRA benchmark modules that we ran.  CPU arithmetic and multimedia performance was right on par with the reference data, and memory bandwidth peaked at over 9.5GB/s.

We also ran the 790GX-based Gigabyte MA790GP-DS4H motherboard through Futuremark’s latest system performance metric built especially for Windows Vista, PCMark Vantage. PCMark Vantage runs through a host of different usage scenarios to simulate different types of workloads including High Definition TV and movie playback and manipulation, gaming, image editing and manipulation, music compression, communications, and productivity.  Most of the tests are multi-threaded, so they can exploit the additional resources offered by a quad-core CPU.

Futuremark PCMark Vantage Simulated Application Performance

Before we get to the benchmark comparisons, we have a bit of explaining to do.  We initially wanted to compare the 790GX to IGPs from NVIDIA and Intel, using similarly priced processors.  For the nForce 780a, we had no problem.  But the brand new G45 motherboard we had on hand did not support our Q6600 processor and the lowest clocked, compatible quad-core we had on hand was the Q9650.  On top of that, the G45 board did not support multiplier manipulation, so we had to run everything stock.  For reference, we have also included scores from a 790FX and X48 using discreet graphics, but with the X48 we were able to use the Q6600, which is a more fair comparison to the sub-$200 Phenom X4 9850.

With that said, the PCMark Vantage results put the 790GX in a very positive light.  AMD's new chipset outperformed the nForce 780a across the board and hung tight with the more expensive offerings that used discreet graphics.

In our custom LAME MT MP3 encoding test, we convert a large WAV file to the MP3 format, which is a popular scenario that many end users work with on a day-to-day basis to provide portability and storage of their digital audio content.  LAME is an open-source mid to high bit-rate and VBR (variable bit rate) MP3 audio encoder that is used widely around the world in a multitude of third party applications.

LAME MT Audio Encoding

In this test, we created our own 223MB WAV file (a hallucinogenically-induced Grateful Dead jam) and converted it to the MP3 format using the multi-thread capable LAME MT application in single and multi-thread modes. Processing times are recorded below, listed in seconds. Once again, shorter times equate to better performance. 

Our custom LAME MT benchmark showed no performance variation between the AMD-powered platforms.  The 790GX, 790FX, and nForce 780a all put up the exact same scores in the single and multi-threaded tests.

Kribibench v1.1 CPU-Bound 3D Rendering

For this next batch of tests, we ran Kribibench v1.1, a 3D rendering benchmark produced by the folks at Adept Development.  Kribibench is an SSE aware software renderer where a 3D model is rendered and animated by the host CPU and the average frame rate is reported.  We used two of the included models with this benchmark: a "Sponge Explode" model consisting of over 19.2 million polygons and the test suite's "Ultra" model that is comprised of over 16 billion polys.

The Kribibench tests we ran also put the 790GX in a positive light.  AMD's new chipset just edged past the nForce 780a and almost hit the mark set by the 790FX.

Cinebench R10 is an OpenGL 3D rendering performance test based on Cinema 4D. Cinema 4D from Maxon is a 3D rendering and animation tool suite used by 3D animation houses and producers like Sony Animation and many others.  It's very demanding of system processor resources and is an excellent gauge of pure computational throughput.

Cinebench R10 3D Rendering

This is a multi-threaded, multi-processor aware benchmark that renders a single 3D scene and tracks the length of the entire process. The time it took each test system to render the entire scene is represented in the graph below, listed in seconds.

Cinebench didn't seem to play perfectly well with the 790GX.  In the single threaded test, the 790GX actually finished about 10% behind the 780a and 790FX--and this was a repeatable result.  The new 790GX, however, managed to come back in the multi-threaded test to finish right in between the 780a and 790FX.

Futuremark 3DMark06 Synthetic DirectX Gaming

3DMark06's built-in CPU test is a multi-threaded DirectX gaming metric that's useful for comparing relative performance between similarly equipped systems.  This test consists of two different 3D scenes that are processed with a software renderer that is dependent on the host CPU's performance.  Calculations that are normally reserved for your 3D accelerator are instead sent to the CPU for processing and rendering.  The frame-rate generated in each test is used to determine the final score.

3DMark06's built-in CPU benchmark put the AMD 790GX just behind the nForce 780a and 790FX.  The 26 - 96 point deltas, however, equate to a maximum difference of only 2.8%.

For our next set of tests, we moved on to some in-game benchmarking with Crysis and F.E.A.R. When testing motherboards or processors with Crysis or F.E.A.R., we drop the resolution to 800x600, and reduce all of the in-game graphical options to their minimum values to isolate CPU and memory performance as much as possible.  However, the in-game effects, which control the level of detail for the games' physics engines and particle systems, are left at their maximum values, since these actually do place some load on the CPU rather than GPU.

Low-Resolution Gaming: Crysis and F.E.A.R. Taking the GPU out of the Equation

Our low-resolution in-game testing speak to one of the main strengthes of the AMD 790GX chipset--its relatively powerful IGP.  In both our F.E.A.R. and Crysis benchmarks, the 790GX blows the competition from NVIDIA and Intel right out of the water.  The AMD 790GX's performance in our in-game tests was simply on another level in comparison to competing IGPs.

We also did some quick testing of the AMD 790GX's video processing engine as it is implemented on the Gigabyte MA790GP-DS4H, in terms of both image quality and CPU utilization with some HQV and H.264 playback tests.

Video Playback Performance: SD and HD HQV and H.264

HQV is comprised of a sampling of SD video clips and test patterns that have been specifically designed to evaluate a variety of interlaced video signal processing tasks, including decoding, de-interlacing, motion correction, noise reduction, film cadence detection, and detail enhancement. As each clip is played, the viewer is required to "score" the image based on a predetermined set of criteria. The numbers listed below are the sum of the scores for each section. We played the HQV DVD using the latest version of Cyberlink's PowerDVD Ultra, with hardware acceleration for NVIDIA PureVideo, ATI UVD, and Intel video acceleration extensions enabled.
 

The AMD 790GX performed very well in the HQV benchmark, besting the Intel and NVIDIA solutions by a small margin. Had some graphical anomalies not cropped up in the Horizontal and Vertical scroll tests, the 790GX would have performed much like ATI's discreet graphics solutions, which is to say it was quite good.

Next we conducted a test using an H.264 encoded movie clip which is available for download from NASA's HD showcase website.  The CPU utilization data gathered during this tests was taken from Windows Vista's built-in Performance Monitor. The graphs show the CPU utilization for the 790GX's IGP while playing back the 1080i QuickTime clip. As you can see, utilization was quite low.  HD video playback shouldn't be a problem for this chipset.
 

Before we bring this article to a close, we'd like to cover a few final data points. Throughout all of our benchmarking and testing, we monitored how much power our test systems were consuming using a power meter. Our goal was to give you all an idea as to how much power each configuration used while idling and under a heavy workload. Please keep in mind that we were testing total system power consumption at the outlet here, not just the power being drawn by the motherboards alone.

Total System Power Consumption Tested at the Outlet

In comparison to the other chipsets for the AMD platform, the 790GX proved to be a relatively low-power solution, besting the nForce 780a and obviously the 790FX (which requires a graphics card) in both idle and peak power consumption.  In comparison to the G45, however, even with a much higher clocked and better performing processor at the heart of the system, the G45 puts up significantly lower power numbers, which is a testament to Intel's Core 2 architecture and 45nm manufacturing process.

Performance Summary: AMD's new 790GX chipset proved to be a solid performer throughout our entire battery of benchmarks.  In all of the more processor and memory bound tests, the 790GX performed on-par with or slightly ahead of NVIDIA's nForce 780a chipset and just behind AMD's own 790FX.  In terms of IGP performance, the 790GX outperformed offerings from both Intel and NVIDIA in both in-game benchmarks that we ran and by a very large margin.

The combination of AMD's new 790GX Northbridge and SB750 Southbridge result in the most well rounded and feature-rich chipset for the AMD platform released to date. The platform should appeal to cost conscious consumers due to its strong performance, excellent IGP, and relatively affordable $150 (give or take) price point. Casual gamers can get by with just the 790GX's IGP or add a low-end discreet Radeon to the equation for somewhat better gaming performance through the use of CrossFireX. And hardcore AMD enthusiasts will no doubt be intrigued by the platform's SB750 Southbridge with Advanced Clock Calibration (ACC), which enhances the overclocking potential of Phenom processors, not to mention the chipset's full support for dual graphics configurations, even if each PEG slot features only 8 PCI Express lanes.  We should note that the SB750, however, won't be exclusive to the 790GX.  A new wave of 790FX motherboards featuring the SB750 should arrive in the not too distant future as well, which will also support ACC.

AMD has clearly been on somewhat of a roll as of late. The graphics division is firing on all cylinders and the chipset division is also performing well, which the launch of the 790GX proves. The Phenom may not compete as favorably with Intel's higher clocked Core 2 Quad processors, but in terms of value, there is no denying AMD's overall platform has solid appeal. Who would have thought that consumers would be able to buy a quad-core Phenom processor with a motherboard based on AMD's most feature rich chipset for about $350 when the Athlon 64 FX processor used to command $1000 alone. It may not be as beneficial to the company's bottom line, but it sure is more attractive to consumers. For the masses out there considering a midrange system upgrade, do yourself a favor and consider AMD. The combination of a relatively low-cost Phenom quad-core CPU, a 790GX-based motherboard, and some inexpensive DDR2 memory, offers solid performance that won't break the bank.

Great IGP ACC Enhanced Overclocking Low Power Affordable

Intel Still has Lower Power Overall Only Dual x8 PEG slots