The performance GPU segment is focused on gaming at a low price point with the added benefit of being a good productivity card on the side. This results in a GPU that is more powerful than the mainstream segment at a slightly higher price point. A playable resolution of 1920×1080 in most current games is to be expected, in many cases with at least mid-range settings (moderate quality settings, 2-4xMSAA, some ansiotropic filtering).
The Radeon HD 6790 (Barts LE) is a fallout part from the 6800 (Barts) production line—essentially it’s a 6870 that failed a quality check at full specs, but works just fine with some combination of lower-specced hardware. Once a combination of working clock speeds and disabled parts is found, a new product is designated. In the case of the Radeon HD 6790, a slower core clock is used, two texure units are disabled, and half of the render output units (ROPs) are disabled. The benefit is all the 6800 Series features are present, including full support for hardware-accelerated Blu-ray 3D, DivX and XviD content. This is in contrast to the Radeon HD 6770 and HD 6750, which were rebranded from HD 5700 Series and upgraded to include support for Blu-ray 3D alone.
Recently, SAPPHIRE sent us their Radeon HD 6790 for evaluation. Aside from a different graphic on the fan shroud, it’s identical in appearance to SAPPHIRE’s Radeon HD 6870. The box contains the card, driver DVD, install instructions, and a DVI-VGA adapter.
The SAPPHIRE Radeon HD 6790 100316L Video Card retails for $149.99
- GPU Family: Barts LE
- Interface: PCI Express 2.1 x16
- RAM size/type: 1GB GDDR5
- 3D API support: DirectX 11, OpenGL 4.1
- GPGPU API support: OpenCL 1.1, DirectCompute
- Output Ports:
- 2x DVI (one single link, one dual link)
- HDMI 1.4a
- DisplayPort 1.2
- Core speed: 840MHz
- RAM speed: 1050MHz (4200MHz effective)
- Core config (unified shaders : texture units : render output units): 800:40:16
- RAM bus width: 256-bit
- TDP (idle/load): 19W/150W
- Supports Eyefinity, AMD HD3D, Shader Model 5.0, Enhanced Unified Video Decoder 3 (UVD3), CrossfireX
The Radeon HD 6790 requires two six-pin PCI Express power connections, which seems a bit confusing at first. A card with a 150W max TDP should only need a single connection (75W through the slot, 75W through a single six-pin PCIe power plug). Since this is a fallout part, and not a brand new design, it’s easier (and probably less expensive) than removing something that’s already there. Also, if you want to do any overclocking you’ll need the extra power afforded by the second connection, so it’s probably a good thing to leave it on.
While the reference AMD Radeon HD 6790 supports up to six displays with a pair of DisplayPort 1.2 outputs, our SAPPHIRE card only has one DisplayPort jack, which limits the card to five. Achieving the maximum requires a DisplayPort 1.2-compatible hub or displays, which allows up to three displays to be run off of the included DP1.2 port. The other two displays, meanwhile, can be connected to any combination of the card’s HDMI or DVI ports.
One Crossfire connector allows for a second Radeon HD 6790 in the system.
So how much more performance does an extra $50 buy?
This comparison between the Sapphire Radeon HD 6790 and the Radeon HD 6670 is intended to show the difference between GPU classes at the same settings.
All testing was performed on our AMD test bench.
Power & Heat
The Radeon HD 6790 uses about 18% more power than the Radeon HD 6670 at idle. That gap actually narrows to 10% during 3DMark 11, but once Metro 2033 is running it grows to 34%.
This card does seem to run a little on the warm side once a load is applied, but it’s nothing to be concerned about.
PCMark Vantage tests overall system performance in a variety of common tasks such as photo editing, video editing, music, gaming, communications, productivity, and security. An overall score and individual scores for each test component are provided.
The more powerful Radeon HD 6790 does improve the gaming score slightly, but the overall system score doesn’t move as much.
3DMark Vantage is a DirectX 10 benchmark application. It provides two GPU tests, two CPU tests, and six feature tests. Tests include shadow maps, cloth simulation, ray-tracing effects, physics, pixel shaders, and parallax occlusion mapping.
The more gaming-focused 3DMark Vantage shows a much greater improvement in score for the Radeon HD 6790. In fact, it nearly doubles the Radeon HD 6670′s GPU score.
3DMark 11 tests the DirectX 11 capability of a system including tessellation, compute shaders, and multithreading. It’s a pretty intense benchmark and visually stunning to boot (this is quite helpful when watching multiple runs of a benchmark).
The same results show in 3DMark 11, with the Radeon HD 6790 performing significantly better than the 6670.
DirectCompute Benchmark tests general-purpose computing on both the CPU and GPU. It uses both DirectCompute and OpenCL APIs to calculate large quantities of FFT-like data and memory transfers.
The Radeon HD 6790 is much better suited to GPGPU tasks than the Radeon HD 6670. Light to moderate tasks should be no problem.
Unigine Heaven 2.5
Unigine Heaven is a DirectX 11 GPU benchmark based on the Unigine engine. Its amazing artwork makes heavy use of tessellation, ambient occlusion, and dynamic lighting.
The extra hardware and slight clock advantage of the Radeon HD 6790 lead to a nearly universal doubling of the 6670′s performance in the Heaven Benchmark.
When it comes to OpenGL, the Radeon HD 6790 holds the slightest of leads over the Radeon HD 6670.
Crysis plays pretty well on the Radeon HD 6790. At 1920×1080 Mainstream quality is very playable. Moving up to Gamer quality gives a minimum frame rate just below acceptable, but moving down to 1680×1050 allows the higher quality setting to become playable.
Metro 2033 is a prime example of the benefits to moving up from mainstream to performance class cards. Where the Radeon HD 6670 couldn’t handle Metro 2033 with 4xMSAA and 16xAF, the Radeon HD 6790 is able to play at those settings with quality turned to medium. Not bad.
Aliens vs Predator
Aliens vs Predator is pretty rough on GPUs, but the Radeon HD 6790 is able to handle some very low settings at 1920×1080
There aren’t many cards that can’t handle H.A.W.X. with the settings turned all the way up.
H.A.W.X. 2, like its predecessor, will play nicely on just about any modern GPU you can throw at it. The big difference (and primary reason for lower performance) is the addition of DirectX 11. The Radeon HD 6790 handles is quite well though.
Warhammer 40,000: Dawn of War II
Warhammer 40,000: Dawn of War II is a real-time strategy (RTS) game, so the minimum frame rate isn’t quite as critical. At 1920×1080 on Ultra settings, the Radeon HD 6790 is a great performer.
Batman: Arkham Asylum
Like H.A.W.X., Batman: Arkham Asylum at full settings doesn’t present any kind of an issue for the Radeon HD 6790.
Lost Planet 2
Lost Planet 2 poses a good challenge for the Radeon HD 6790. While the game is playable at 1920×1080, you’ll have to choose between DirectX 11 features and antialiasing. Both just can’t be enabled at this resolution.
Best Playable Settings
These are the highest settings that achieve a playable experience, meaning for all but the RTS games a minimum of 30 frames per second is required. Unfortunately not all of the games report a minimum frame rate. In those cases, the average frame rate will be used.
40fps min, 70fps avg @ 1920×1080, Mainstream quality, 8xAA
17fps min, 35fps avg @ 1920×1080, Medium quality, 16xAF, 4xMSAA
Note: The test produces a few quick dips below 30fps at the start of each run for both listed resolutions, but the rest of the time we’re up around the 38fps mark. Dropping to the lowest available resolution of 1024×768 yeilds the same kind of results. The same thing happens on the Radeon HD 6950, so it’s really not much to be concerned about.
Aliens vs Predator
34fps avg @ 1920×1080, 2xFSAA, 1xAF, Tessellation off, Advanced Shadows off
118fps avg @ 1920×1080, 8xAA
52fps avg @ 1920×1080, 8xAA, DX11 features on
Warhammer 40,000: Dawn of War II
Since Dawn of War II is a real-time strategy game a lot more leeway is justified in frame rate. The game is playable at these settings, although if you’re dead set on having a 30+fps minimum, reducing settings to low will produce the desired results.
Batman: Arkham Asylum
56fps min, 88fps avg @ 1920×1080, Very High quality, 8xAA
Lost Planet 2
35.6fps avg @ 1920×1080, 0xMSAA, Motion Blur on, Shadow detail High, Texture Detail High, Rendering level High, DX11 features Low
Just like the Radeon HD 6670, the Radeon HD 6790 is capable of multiple displays and Eyefinity gaming. The Radeon HD 6790 supports four displays natively, although to use the fourth display a DisplayPort hub or display that supports daisy chaining are required. A three-display setup is great for productivity if you require lots of documents or other windows open simultaneously. AMD’s Catalyst Control Center makes it easy to create and configure an Eyefinity display group.
Since this is a gaming focused card, we’ll see just how high the settings can be raised while maintaining a playable experience.
Batman: Arkham Asylum: 31/53/43 @ Very High detail, 4xMSAA
H.A.W.X. 2: 32/46 fps (avg/max) @ 4xMSAA, DirectX 11 features on (Maximum settings – 8xAA wasn’t an available option for some reason)
Crysis: Warhead: 46/78/64 (min/max/avg) @ Performance, 8xAA
The SAPPHIRE Radeon HD 6790 is a good card. It’s a little power hungry, but that’s because it comes from a much higher-end card. Performance really leaves nothing to complain about—most games are playable at mid-range quality settings at 1920×1080. If you have an Eyefinity setup you’ll be able to play with some decent quality settings as well. It’s definitely worth the extra $50 over the Radeon HD 6670 if you can afford it (and need the extra power).
If you’re building a gaming system on a budget and can’t afford the jump to a higher performance GPU, the SAPPHIRE Radeon HD 6790 is a good choice for your system. We’re happy to award it the Icrontic Stamp of Approval.