AMD Radeon HD 6790 Video Card Review
By Gabriel Torres on April 5, 2011


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.

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.

AMD Radeon HD 6790 reference model
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Figure 1: AMD Radeon HD 6790 reference model

AMD Radeon HD 6790 reference model
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Figure 2: AMD Radeon HD 6790 reference model

This video card has two DVI-D connectors, one HDMI connector, and two mini DisplayPort connectors.

AMD Radeon HD 6790 reference model
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Figure 3: Video connectors

The AMD Radeon HD 6790 (Contíd)

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.

AMD Radeon HD 6790 reference model
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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.

AMD Radeon HD 6790 reference model
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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.

AMD Radeon HD 6790 reference model
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Figure 6: The GPU heatsink

AMD Radeon HD 6790 reference model
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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.

AMD Radeon HD 6790 reference model
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Figure 8: Memory chips

Before seeing the performance results, let’s recap the main features of this video card.

Main Specifications

The main specifications for the reference model of the Radeon HD 6790 video card include:

How We Tested

During our benchmarking sessions, we used the configuration listed below. Between our benchmarking sessions the only variable was the video card being tested.

Hardware Configuration

Software Configuration

Driver Versions

Software Used

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.

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, 1680x1050 and 1920x1200, 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.

Radeon HD 6790

Call of Duty 4 - Maximum

1680x1050

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%

Radeon HD 6790

Call of Duty 4 - Maximum

1920x1200

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%

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 1680x1050 and 1920x1200 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.

Radeon HD 6790

Crysis Warhead - High

1680x1050

Difference

Radeon HD 6850

39

15%

Radeon HD 6790

34

 

GeForce GTX 550 Ti

32

6%

Radeon HD 5770

28

21%

Radeon HD 6790

Crysis Warhead - High

1920x1200

Difference

Radeon HD 6850

34

17%

Radeon HD 6790

29

 

GeForce GTX 550 Ti

27

7%

Radeon HD 5770

24

21%

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 1680x1050 and 1920x1200, 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.

Radeon HD 6790

FarCry 2 - Very High

1680x1050

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%

Radeon HD 6790

FarCry 2 - Very High

1920x1200

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%

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 1680x1050 and 1920x1200, with texture set at “medium,” shadows set at “low,” 4x anisotropic filtering and no anti-aliasing.

Radeon HD 6790

Aliens vs. Predator

1680x1050

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%

Radeon HD 6790

Aliens vs. Predator

1920x1200

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%

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 1680x1050 and 1920x1200. The results below are the number of frames per second generated by each video card.

Radeon HD 6790

Lost Planet 2

1680x1050

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%

Radeon HD 6790

Lost Planet 2

1920x1200

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%

3DMark 11 Professional

3DMark 11 Professional measures Shader 5.0 (i.e., DirectX 11) performance. We ran this program at 1680x1050 and 1920x1200, 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.

Radeon HD 6790

3DMark 11 - Performance

1680x1050

Difference

Radeon HD 6850

2254

13%

Radeon HD 6790

2001

 

Radeon HD 5770

1775

13%

GeForce GTX 550 Ti

1694

18%

Radeon HD 6790

3DMark 11 - Performance

1920x1200

Difference

Radeon HD 6850

1760

15%

Radeon HD 6790

1532

 

Radeon HD 5770

1336

15%

GeForce GTX 550 Ti

1313

17%

Radeon HD 6790

3DMark 11 - Extreme

1680x1050

Difference

Radeon HD 6850

1227

16%

Radeon HD 6790

1056

 

Radeon HD 5770

960

10%

GeForce GTX 550 Ti

953

11%

Radeon HD 6790

3DMark 11 - Extreme

1920x1200

Difference

Radeon HD 6850

984

14%

Radeon HD 6790

860

 

Radeon HD 5770

775

11%

GeForce GTX 550 Ti

750

15%

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.

Originally at http://www.hardwaresecrets.com/article/AMD-Radeon-HD-6790-Video-Card-Review/1236


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