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[nextpage title=”Introduction”]
The new Radeon HD 6790 comes with a USD 150 suggested price, positioning it between the Radeon HD 5770 and the Radeon HD 6850, and competing directly with the GeForce GTX 550 Ti from NVIDIA. Let’s see if this video card is a good buy.
We are reviewing the reference model of the Radeon HD 6790 provided by AMD. While the performance of Radeon HD 6790 provided by other companies may be the same, the design of the video card may be different, depending upon whether the manufacturer decided to create its own design or follow AMD’s ready-made design. Also, it is very important to understand that manufacturers will probably offer Radeon HD 6790 video cards running at higher clock rates than the reference model.
In the table below we compare the main specs of the video cards included in our review. They are all DirectX 11 parts. The prices listed below do not include rebates. Prices were researched at Newegg.com on the day we published this review, except for the Radeon HD 6790, that we are publishing at the suggested price according to AMD.
| Video Card | Core Clock | Shader Clock | Memory Clock (Real) | Memory Clock (Effective) | Memory Interface | Memory Transfer Rate | Memory | Shaders | Price |
| GeForce GTX 550 Ti | 900 MHz | 1,800 MHz | 1,025 MHz | 4.1 GHz | 192-bit | 98.4 GB/s | 1 GB GDDR5 | 192 | USD 125 – USD 152 |
| Radeon HD 5770 | 850 MHz | 850 MHz | 1.2 GHz | 4.8 GHz | 128-bit | 76.8 GB/s | 1 GB GDDR5 | 800 | USD 120 – 140 |
| Radeon HD 6790 | 840 MHz | 840 MHz | 1 GHz | 4 GHz | 256-bit | 128 GB/s | 1 GB GDDR5 | 800 | USD 150 |
| Radeon HD 6850 | 775 MHz | 775 MHz | 1 GHz | 4 GHz | 256-bit | 128 GB/s | 1 GB GDDR5 | 960 | USD 165 – 185 |
You can compare the specs of these video cards with other video cards by taking a look at our AMD ATI Chips Comparison Table and NVIDIA Chips Comparison Table tutorials.
Now let’s take an in-depth look at the reference model of the Radeon HD 6790.
[nextpage title=”The AMD Radeon HD 6790″]
Below we have an overall look at the AMD reference model of the Radeon HD 6790. It requires two six-pin auxiliary power connectors.
Figure 1: AMD Radeon HD 6790 reference model
Figure 2: AMD Radeon HD 6790 reference model
This video card has two DVI-D connectors, one HDMI connector, and two mini DisplayPort connectors.
Figure 3: Video connectors
[nextpage title=”The AMD Radeon HD 6790 (Cont’d)”]
In Figure 4, you can see the video card with its cooler removed and, in Figure 5, a close-up of the voltage regulator circuit.
Figure 4: Video card with the cooler removed
The voltage regulator circuit of the reference model uses solid capacitors, ferrite-core coils (which make the regulator to have higher efficiency because they have lower energy loss than iron-core coils), and low RDS(on) MOSFET transistors (i.e., higher efficiency). This circuit uses a four-phase design to generate the GPU voltage.
Figure 5: Voltage regulator circuit
The GPU heatsink can be seen in Figures 6 and 7. It has a copper base, three copper heatpipes (two five-mm and one eight-mm), aluminum fins, and a 75 mm radial fan.
Figure 6: The GPU heatsink
Figure 7: The GPU heatsink
The Radeon HD 6790 reference model uses eight 1 Gbit GDDR5 memory chips, making its 1 GB memory (1 Gbit x 8 = 1 GB). The chips used are H5GQ1H24AFR-T2C parts from Hynix, which support up to 1.25 GHz (5 GHz QDR). Since on this video card memory is accessed at 1 GHz (4 GHz QDR), there is still a huge 25% margin for you to increase the memory clock rate while keeping the chips inside the maximum they support. Of course you can always try to overclock the memory chips above their specs.
Figure 8: Memory chips
Before seeing the performance results, let’s recap the main features of this video card.
[nextpage title=”Main Specifications”]
The main specifications for the reference model of the Radeon HD 6790 video card include:
- Graphics chip: AMD Radeon HD 6790 running at 800 MHz
- Memory: 1 GB GDDR5 memory (256-bit interface) from Hynix (H5GQ1H24AFR-T2C), running at 1 GHz (4 GHz, QDR)
- Bus type: PCI Express x16 2.0
- Video Connectors: Two DVI-D, one HDMI, and two mini DisplayPort
- Video Capture (VIVO): No
- Cables and adapters that come with this board: NA
- Number of CDs/DVDs that come with this board: NA
- Games included: NA
- Programs included: NA
- More information: https://www.amd.com
- MSRP in the US: USD 150
[nextpage title=”How We Tested”]
During our benchmarking sessions, w
e used the configuration listed below. Between our benchmarking sessions the only variable was the video card being tested.
Hardware Configuration
- CPU: Core i7 Extreme 965 (3.2 GHz, 8 MB L2 memory cache)
- Motherboard: MSI Big Bang XPower (1.5 BIOS)
- Memories: 3x 2 GB G.Skill F3-10666CL7T-6GBPK (DDR3-1333/PC3-10666, CL7-7-7-18)
- Hard disk drive: Western Digital VelociRaptor WD3000GLFS (300 GB, SATA-300, 10,000 rpm, 16 MB cache)
- Video monitor: Samsung SyncMaster 305T (30” LCD, 2560×1600)
- Power Supply: SilverStone Element ST75EF
- CPU Cooler: Intel stock
- Optical Drive: LG GSA-H54N
Software Configuration
- Windows 7 Ultimate 64-bit
- Video resolution: 2560×1600 @ 60 Hz
Driver Versions
- AMD video driver version: Catalyst 11.3 (Radeon HD 5770 and 6850)
- AMD video driver version: 8.84.2 Beta (Radeon HD 6790)
- NVIDIA video driver version: 266.58
- Intel Inf driver version: 9.1.2.1008
Software Used
- 3DMark 11 Professional 1.0.0
- Aliens vs. Predator + Benchmark Tool
- Call of Duty 4 – Patch 1.7
- Crysis Warhead – Patch 1.1 + HOC Bench Crysis Warhead Benchmark Tool 1.1.1
- Far Cry 2 – Patch 1.03
- Lost Planet 2
- StarCraft II: Wings of Liberty – Patch 1.1.0
Error Margin
We adopted a 3% error margin. Thus, differences below 3% cannot be considered relevant. In other words, products with a performance difference below 3% should be considered as having similar performance.
[nextpage title=”Call of Duty 4″]
Call of Duty 4 is a DirectX 9 game implementing high-dynamic range (HDR) and its own physics engine, which is used to calculate how objects interact. For example, if you shoot, exactly what will happen to the object when the bullet hits it? Will it break? Will it move? Will the bullet bounce back? It gives a more realistic experience to the user.
To get accurate results, we had to disable the 80 FPS limit in the game. To do this, input the command, “/seta com_maxfps 1000” (minus the quotes) into the console (` key). It can be set to any number greater than 200.
We ran this program at two 16:10 widescreen resolutions, 1680×1050 and 1920×1200, maxing out all image quality controls (i.e., everything was set to the maximum values in the Graphics and Texture menus). We used the internal game benchmarking feature, running a demo provided by NVIDIA called “wetwork.” We are putting this demo here for downloading if you want to run your own benchmarks. We ran the demo five times, and the results below are the average number of frames per second (FPS) achieved by each video card.
| Call of Duty 4 – Maximum | 1680×1050 | Difference |
| Radeon HD 6850 | 122.2 | 22% |
| Radeon HD 6790 | 99.9 | |
| GeForce GTX 550 Ti | 93.6 | 7% |
| Radeon HD 5770 | 92.4 | 8% |
| Call of Duty 4 – Maximum | 1920×1200 | Difference |
| Radeon HD 6850 | 105.3 | 25% |
| Radeon HD 6790 | 84.2 | |
| GeForce GTX 550 Ti | 78.8 | 7% |
| Radeon HD 5770 | 76.8 | 10% |
[nextpage title=”Crysis Warhead”]
Crysis Warhead is a DirectX 10 game based on the same engine as the original Crysis, but optimized (it runs under DirectX 9.0c when installed on Windows XP).
We used the HardwareOC Crysis Warhead Benchmark Tool to collect the data for this test. We ran this program at 1680×1050 and 1920×1200 at high image quality (but with no anti-aliasing and no anisotropic filtering) and using the Airfield demo. The results below are the number of frames per second achieved by each video card.
| Crysis Warhead – High | 1680×1050 | Difference |
| Radeon HD 6850 | 39 | 15% |
| Radeon HD 6790 | 34 | |
| GeForce GTX 550 Ti | 32 | 6% |
| Radeon HD 5770 | 28 | 21% |
| Crysis Warhead – High | 1920×1200 | Difference |
| Radeon HD 6850 | 34 | 17% |
| Radeon HD 6790 | 29 | |
| GeForce GTX 550 Ti | 27 | 7% |
| Radeon HD 5770 | 24 | 21% |
[nextpage title=”Far Cry 2″]
Far Cry 2 is based on an entirely new game engine called Dunia, which is DirectX 10 when played under Windows Vista with a DirectX 10 compatible video card.
We used the benchmarking utility that comes with this game at 1680×1050 and 1920×1200, setting image quality to Very High (with x4 anti
-aliasing) and running the “Ranch Long” demo three times. The results below are expressed in frames per second and are an arithmetic average of the three results collected.
| FarCry 2 – Very High | 1680×1050 | Difference |
| Radeon HD 6850 | 83.1 | 20% |
| Radeon HD 6790 | 69.0 | |
| GeForce GTX 550 Ti | 67.8 | 2% |
| Radeon HD 5770 | 61.6 | 12% |
| FarCry 2 – Very High | 1920×1200 | Difference |
| Radeon HD 6850 | 73.1 | 24% |
| Radeon HD 6790 | 58.8 | |
| GeForce GTX 550 Ti | 57.2 | 3% |
| Radeon HD 5770 | 53.3 | 10% |
[nextpage title=”Aliens vs. Predator”]
Aliens vs. Predator is a DirectX 11 game that makes full use of tessellation and advanced shadow rendering. We used the Aliens vs. Predator Benchmark Tool developed by Rebellion. This program reads its configuration from a text file (our configuration files can be found here). We ran this program at 1680×1050 and 1920×1200, with texture set at “medium,” shadows set at “low,” 4x anisotropic filtering and no anti-aliasing.
| Aliens vs. Predator | 1680×1050 | Difference |
| Radeon HD 6850 | 46.6 | 9% |
| Radeon HD 6790 | 42.8 | |
| Radeon HD 5770 | 38.9 | 10% |
| GeForce GTX 550 Ti | 35.1 | 22% |
| Aliens vs. Predator | 1920×1200 | Difference |
| Radeon HD 6850 | 37.7 | 10% |
| Radeon HD 6790 | 34.3 | |
| Radeon HD 5770 | 31.1 | 10% |
| GeForce GTX 550 Ti | 28.0 | 23% |
[nextpage title=”Lost Planet 2″]
Lost Planet 2 is a game that uses a lot of DirectX 11 features, like tessellation (to round out the edges of polygonal models), displacement maps (added to the tessellated mesh to add fine grain details), DirectCompute soft body simulation (to introduce more realism in the “boss” monsters), and DirectCompute wave simulation (to introduce more realism in the physics calculations in water surfaces; when you move or when gunshots and explosions hit the water, it moves accordingly). We reviewed the video cards using Lost Planet 2 internal benchmarking features, choosing the “Benchmark A” (we know that “Benchmark B” is the one recommended for reviewing video cards, however, at least with us, results were inconsistent). We set graphics at “high,” no anti-aliasing and DX11 at “full,” at 1680×1050 and 1920×1200. The results below are the number of frames per second generated by each video card.
| Lost Planet 2 | 1680×1050 | Difference |
| Radeon HD 6790 | 36.4 | |
| Radeon HD 6850 | 36.3 | 0% |
| GeForce GTX 550 Ti | 34.1 | 7% |
| Radeon HD 5770 | 24.8 | 47% |
| Lost Planet 2 | 1920×1200 | Difference |
| Radeon HD 6850 | 33.3 | 11% |
| Radeon HD 6790 | 30.1 | |
| GeForce GTX 550 Ti | 28.8 | 5% |
| Radeon HD 5770 | 22.2 | 36% |
[nextpage title=”3DMark 11 Professional”]
3DMark 11 Professional measures Shader 5.0 (i.e., DirectX 11) performance. We ran this program at 1680×1050 and 1920×1200, selecting the four graphics tests available and deselecting the other tests available. We used two image quality settings, “Performance” and “Extreme,” both at their default settings. The results being compared are the “GPU Score” achieved by each video card.
| 3DMark 11 – Performance | 1680×1050 | Difference |
| Radeon HD 6850 | 2254 | 13% |
| Radeon HD 6790 | 2001 | |
| Radeon HD 5770 | 1775 | 13% |
| GeForce GTX 550 Ti | 1694 | 18% |
| 3DMark 11 – Performance | 1920×1200 | Difference |
| Radeon HD 6850 | 1760 | 15% |
| Radeon HD 6790 | 1532 | |
| Radeon HD 5770 | 1336 | 15% |
| GeForce GTX 550 Ti | 1313 | 17% |
| 3DMark 11 – Extreme | 1680×1050 | Difference |
| Radeon HD 6850 | 1227 | 16% |
| Radeon HD 6790 | 1056 | |
| Radeon HD 5770 | 960 | 10% |
| GeForce GTX 550 Ti | 953 | 11% |
| 3DMark 11 – Extreme | 1920×1200 | Difference |
| Radeon HD 6850 | 984 | 14% |
| Radeon HD 6790 | 860 | |
| Radeon HD 5770 | 775 | 11% |
| GeForce GTX 550 Ti | 750 | 15% |
[nextpage title=”Conclusions”]
The new Radeon HD 6790 is a serious competitor to the GeForce GTX 550 Ti. In our tests, this new video card from AMD was up to 23% faster than its competitor, except on Far Cry 2, where both video cards achieved the same performance level. The GeForce GTX 550 Ti has as advantage at the moment: its price, which dropped since its release date. Originally sold at USD 150, you can find some models for as low as USD 125. The price of the Radeon HD 6790 will probably drop from the suggested price of USD 150 as soon as AMD partners start offering it, but this can take a couple of weeks to occur.
As promised by AMD, the Radeon HD 6790 is really between the Radeon HD 5770 and the Radeon HD 6850. So, you may also consider buying the cheaper Radeon HD 5770 (the Radeon HD 6790 was between 8% and 47% faster than the Radeon HD 5770 in our tests) or the more expensive Radeon HD 6850 (which was up to 25% faster than the Radeon HD 6790 in our tests), depending on your budget.