XFX HD6850 CrossFireX review

1. Introduction2. The Architecture3. The XFX HD68504. Testing Methodology5. Unigine Heaven Benchmark6. 3DMark Vantage7. Alien V Predator8. Far Cry 29. Lost Planet 210. Mafia 211. Metro 203312. Resident Evil 513. Tom Clancy HAWX14. Distributed Computing (RC5-72)15. TessMark16. Shadertoy17. HQV Benchmark 2.018. Power Consumption19. Thermal Dynamics20. Acoustics Performance21. Overclocking22. Closing Thoughts23. View All Pages

When nVidia released the GTX460, everyone was literally blown away – this was a mid range card that utterly dominated the market and delivered staggering levels of performance, particularly when overclocked. AMD had left a big hole in its range, from the 5770 to the 5850 – with only the lightweight 5830 offering any resistance in the £130 to £200 market. The headroom on nVidia's GTX460 card was incredible, with voltage tweakable solutions today hitting 1GHz on the core. AMD haven't been asleep on the job though and the new 6800 series is a direct reply to the serious questions the GTX460 has been asking.

XFX are one of AMD's key partners now, having parted company with nVidia to concentrate solely on AMD graphics cards. For this launch article today we have decided to concentrate on the XFX HD6850, a card which features a custom cooling solution. XFX have told us that this card will be sold for around £155 inc vat – meaning it directly targets reference clocked GTX 460's and overclocked 768mb models.

Firstly, we need to address the naming conventions, the HD6850 isn't a direct replacement for the HD5850, after all the HD5850 was initially released around £250, not £150.

AMD are focusing on tight price points and ensuring they try and deliver the best value for money products to market.

	XFX HD6850
Core Clock Speed	775mhz
Stream Processors	960
ROPs	32
Frame Buffer	1GB GDDR5
Compute Power	1.5 TFLOPs
Memory Width/Speed	256bit, 4.0 GBPS
Idle/Load Board Power	19W/127W
Power Connectors	Single 6 Pin
Display Outputs	2xDVI + 2x mDP + 1 HDMI

The new 6800 series has seen hardware architecture changes with a focus on strengthening tessellation and geometry throughput. Avid readers of KitGuru will have seen over recent months that nVidia Fermi hardware has been leading the way in titles such as UniGine Heaven Benchmark, a synthetic test which relies heavily on Tessellation performance.

The 6800 series has a reconfigured core design which offers up to 2.0 TeraFLOPS and 24 Gigapixels per second performance. The command processor is linked to the graphics engine as seen in the diagram above, with the new generation 7 Tessellator. The Dual rasterizers and 12-14 SIMD engines tied to a 256 bit GDDR5 memory interface help to improve performance beyond the levels of the last generation, while using 25% less silicon.

	AMD HD5850	AMD HD6870
Die Size	334 mm2	255mm2
Transistors	2.15 billion	1.7 billion
Memory Bandwidth	153.6GB/sec	134.4 GB/sec
Geometry Throughput	725 million polygons/sec	900 million polygons/sec
SIMD Engines	18	14
Stream Processors	1440	1120
Texture Units	72	56
Z/Stencil ROPs	128	128
Colour ROPs	32	32
Max Board Power	151W	151W
Idle Power	27W	19W

The table above shows a direct comparison against the HD5850 and HD6870. The HD6870 has less texture units, SIMD engines, Stream Processors with a lower memory bandwidth but the Geometry throughput has been significantly increases from 725 million polygons per second to 900 million polygons per second. The new design is more efficient and with the die shrink requires less power at idle.

	Hardware Tessellator Progression
Generation 1	ATI Radeon 8500	Fixed Function PN Triangles (TRUFORM)
Generation 2	Microsoft Xbox 360	Displacement mapping, adaptive tessellation
Generation 3	AMD Radeon HD2000 family	Dirext X 10 compatibility
Generation 4	AMD Radeon HD 3000 family	Direct X 10.1 compatibility
Generation 5	AMD Radeon HD 4000 family	Performance Enhancements
Generation 6	AMD Radeon HD 5000 family	Direct X 11 compatibility
Generation 7	AMD Radeon HD 6800 Series	Improved Thread Management and buffering

The updated Tessellation unit, called ‘Generation 7' brings new thread management capabilities as well as buffering enhancements to the table. This means that performance is increased by up to two times when directly compared to the HD5000 series. This should mean that AMD are closely competitive with similarly priced nVidia Fermi hardware, we will look at performance later in this article. AMD's internal testing shows that the HD6870 achieves twice the tessellation performance of the HD5870.

Tessellation is a hotly discussed topic right now, and it is a bone of contention between nVidia and AMD. Our recent interview with Richard Huddy opened a few eyes, as he said “nVidia is pushing a single message and that’s tessellation. Tessellation is about enriching detail, and that’s a good thing, but nVidia is pushing to get as much tessellation as possible into everything. With artificial tests like Stone Giant, which was paid for by nVidia, tessellation can be done down to the single pixel level. Even though that pixel can’t be broken away from the 3 other pixels in its quad. Doing additional processing for each pixel in a group of 4 and then throwing 75% of that work away is just sad.”

AMD's stance on this is “Tessellating the Right Way” – which means a focus on the most efficient tessellation usage models with 16 pixels per polygon combining solid image quality with high levels of performance. Adaptive Tessellation is how they want to approach it, using high levels for objects close to the front of the screen (and in eye shot of the gamers) and then switch to lower levels for distant and simple objects to help improve performance while  avoiding geometry aliasing problems.

The image above was captured from Alien V Predator and showcases the new Morphological Anti-Aliasing technique from AMD which is a post process filtering technique accelerated with DirectCompute. It delivers full scene anti Aliasing and it is not limited to polygon edges or alpha tested surfaces. The system is faster than super sampling with similar performance levels to edge detect CFAA, but it applies to all edges. This can be enabled from Catalyst Control Center and is compatible with any Direct X 9/10/11 supported application.

Anistrophic Filtering has also been fine tuned and enhanced with a newly refined algorithm in place. It addresses visible discontinuities in very noisy textures offering smoother transitions between filter levels. It also maintains full performance and angle independence.

Stylish boxes have always been a strength of XFX and this one proves no different. An excellent, futuristic design.

It is not often a company bundles a flyer for their PSU range (in conjunction with Seasonic) with a graphics card, but XFX are keen to make customers aware of their Pro Series range, which we have reviewed in the past on KitGuru. Read the testing here: XFX PRO 650W, Pro 750W and Pro 850W.

We received one of the first XFX HD6850's off the production line so there are no games bundled, however XFX told us that they are supplying Alien V Predator with this bundle. Our bundle was all literature based, with a ‘Do Not Disturb' sign to hang over your door.

The XFX card is finished in a striking black design with a bright pink fan. I have always been a sucker for a black PCB.

The fan is a 9 blade design and is larger than the AMD reference model, which is always good to see. Interestingly, while we are used to seeing ‘warranty void' stickers on power supply screws to stop people tampering, this is the first time we have spotted them on the backplate of a GFX cooler (above left).

The shroud on the card is attractively designed with the name and branding of the product on the sides. This cover has holes all around it which certainly makes the product stand out.

The XFX HD6850 adheres to the AMD reference design with support for 2x mini DP (1.2), HDMI 1.4a, and 2x DL-DVI and SL-DVI connectors. It requires a single 6 pin power connector to operate. We like the fact that this card will expel hot air out the back of the chassis. Also good to notice little touches, such as the XFX name ‘cut' into the backplate, and cooling vents next to the power socket.

The cooler itself is a circular design, a copper and aluminum hybrid design to ensure good cooling characteristics. It reminded us of a Zalman design, although we aren't sure who made it for XFX.

Above, the naked card and a close up of the core and memory chips. These are Hynix H5GQ1H24AFR and we have seen them on many AMD cards in the past.

Above, the XFX HD6850 specifications, which are reference clocks at 775mhz core and 1000mhz (4000mhz effective) on the memory. The image on the right shows two of them running in Crossfire X.

For the review today we have built a strong system which we feel would fit in well with the audience purchasing these cards. We are using a Core i7 950 Quad Core CPU with 6GB of DDR3 memory. We have applied a moderate overclock to the processor because we know you guys never run anything at reference speeds!

We are also going to limit testing to 1920×1080 (1080) and 1920×1200 as less than 1% of the enthusiast user base reading this will have a 30 inch screen – this will address the widest possible audience.

Test System: Validation here.

XFX HD6850

Other cards:
eVGA GTX460 FTW (850/1000)
nVidia GTX460 Talon Attack (1000/1000 & 810/975)
AMD Reference HD6870 (900/1050)
AMD Reference HD5870 (850/1200)
AMD Reference HD5850 (725/1000)
AMD Reference HD5770 (850/1200)
nVidia Reference GTX460 (675/900)
eVGA GTX460 768MB SC (763/950)
nVidia Reference GTX 460 768MB (675/900)
XFX HD5830 XXX (840/1125)
nVidia Reference GTS 450 (850/1000)
XFX HD5750 XXX (740/1200)
AMD reference HD5750 (700/1150)

Other Hardware:
Processor: Intel Core i7 950 @ 3.6ghz
Cooler: Arctic Cooling Freezer 13
Motherboard: ASRock X58 Extreme 6
Memory: Crucial Ballistix Tracer 1600mhz 6GB (3x2GB)
Power Supply: Thermaltake 750W Toughpower Grand
Chassis: Cooler Master CM 690 II
Monitor: Dell Ultrasharp U2410 (A00)

Software:
Windows 7 Ultimate 64 bit

Unigine Heaven Benchmark
3DMark Vantage
HQV Benchmark
Catalyst 10.9 & 10.10 Driver (12th October WHQL) /ati_catalyst_10.9a_appprofile
Fraps Professional
Steam Client
FurMark
Forceware 260.89 beta
Tessmark
Shader Toy

Technical Monitoring and Test Equipment:
Keithley Integra unit
Thermal Diodes
Raytek Laser Temp Gun 3i LSRC/MT4 Mini Temp
Extech digital sound level meter & SkyTronic DSL 2 Digital Sound Level Meter

Games:
Resident Evil 5
Lost Planet 2
Far Cry 2
Tom Clancy H.A.W.X.
Metro 2033
Alien V Predator
Mafia 2

All the latest BIOS updates and drivers are used during testing. We perform under real world conditions, meaning KitGuru tests all games across five closely matched runs and average out the results to get an accurate median figure.

Unigine provides an interesting way to test hardware. It can be easily adapted to various projects due to its elaborated software design and flexible toolset. A lot of their customers claim that they have never seen such extremely-effective code, which is so easy to understand.

Heaven Benchmark is a DirectX 11 GPU benchmark based on advanced Unigine engine from Unigine Corp. It reveals the enchanting magic of floating islands with a tiny village hidden in the cloudy skies. Interactive mode provides emerging experience of exploring the intricate world of steampunk.

Efficient and well-architected framework makes Unigine highly scalable:

• Multiple API (DirectX 9 / DirectX 10 / DirectX 11 / OpenGL) render
• Cross-platform: MS Windows (XP, Vista, Windows 7) / Linux
• Full support of 32bit and 64bit systems
• Multicore CPU support
• Little / big endian support (ready for game consoles)
• Powerful C++ API
• Comprehensive performance profiling system
• Flexible XML-based data structures

1080p is a standard resolution we use with the Heaven Benchmark on all graphics cards, this means all review results are comparible throughout previous months.

Shaders are set to high, Tessellation to normal, anistrophy to 4 and Anti Aliasing is disabled.

The XFX HD6850 in Crossfire delivers a fantastic level of performance, only lagging behind the overclocked eVGA GTX460 FTW solution with 850 core on both cards. The single card results are almost identical to the reference GTX460 768MB card, which is a good result for XFX.

Futuremark released 3DMark Vantage, on April 28, 2008. It is a benchmark based upon DirectX 10, and therefore will only run under Windows Vista (Service Pack 1 is stated as a requirement) and Windows 7.  This is the first edition where the feature-restricted, free of charge version could not be used any number of times. 1280×1024 resolution was used with performance settings.

In CrossfireX the XFX HD6850 score over 22k in 3dmark Vantage at Performance, which is a very good result for a pair of cards costing £150 each. When we compare with the last generation HD5770 running in Crossfire, we can see that this is an improvement of around 5,000 points.

A single card scores 12,589 points which is very close to the eVGA GTX460 768mb Superclocked Edition (12,776 points), another solid result for XFX.

Aliens V Predator has proved to be a big seller since the release and Sega have taken the franchise into new territory after taking it from Sierra. AVP is a Direct X 11 supported title and delivers not only advanced shadow rendering but high quality tessellation for the cards on test today.

To test the cards we used a 1080p resolution with DX11, Texture Quality Very High, MSAA Samples 1, 16 af, ambient occulsion on, shadow complexity high, motion blur on. We use this with most of our graphics card testing so cards are comparible throughout reviews.

Yet again, the XFX HD6850 in Crossfire is right behind the eVGA GTX460 FTW SLI in Sli at 850mhz core. The XFX solution trails by around 6 frames per second however it is worth considering that the XFX HD6850 CFx costs £300 while the eVGA GTX460 FTW retails for around £350.

In single card mode, the HD6850 scores slightly more than the reference clocked GTX460, another strong showing for XFX.

Far Cry 2 (commonly abbreviated as “FC2 or “fc2″) is an open-ended first-person shooter developed by Ubisoft Montreal and published by Ubisoft. It was released on October 21, 2008 in North America and on October 23, 2008 in Europe and Australia. It was made available on Steam on October 22, 2008. Crytek, the developers of the original game, were not involved in the development of Far Cry 2.

Ubisoft has marketed Far Cry 2 as the true sequel to Far Cry, though the sequel has very few noticeable similarities to the original game. Instead, it features completely new characters and setting, as well as a new style of gameplay that allows the player greater freedom to explore different African landscapes such as deserts, jungles, and savannas. The game takes place in a modern-day East African nation in a state of anarchy and civil war. The player takes control of a mercenary on a lengthy journey to locate and assassinate “The Jackal,” a notorious arms dealer.

Far Cry 2 is still a popular game and the open world environment can be taxing on even the latest hardware available today.

Our settings: 1920×1200 (60Hz), D3D10, Fixed Time Step(No), Disable Artificial Intelligence(No), Full Screen, Anti-Aliasing(4x), VSync(No), Overall Quality(Optimal), Vegetation(High), Shading(High), Terrain(High), Geometry(High), Post FX(High), Texture(High), Shadow(High), Ambient(High), Hdr(Yes), Bloom(Yes), Fire(Very High), Physics(Very High), RealTrees(Very High).

The Far Cry 2 engine has always performed better with nVidia hardware and this time the reference clocked GTX460 SLI solution outperforms the XFX HD5850 in CFx by around 2 frames per second. The gap widens when comparing minimum statistics, with the nVidia solution pulling ahead by 14fps.

The Single card results are interesting, because the XFX HD5850 delivers comparible results to the previous class leader – the HD5870. Another great showing from the HD6800 series cards, especially considering the price points.

Lost Planet 2 is a third-person shooter video game developed and published by Capcom. The game is the sequel to Lost Planet: Extreme Condition which is also made by Capcom, taking place ten years after the events of the first game, on the same fictional planet. The story takes place back on E.D.N. III 10 years after the events of the first game. The snow has melted to reveal jungles and more tropical areas that have taken the place of more frozen regions. The plot begins with Mercenaries fighting against Jungle Pirates.

After destroying a mine, the Mercenaries continue on to evacuate the area, in which a Category-G Akrid appears and attacks them. After being rescued, they find out their evacuation point (Where the Category-G appeared) was a set-up and no pick up team awaited them. Lost Planet 2 runs on the MT-Framework 2.0, an updated version of the engine used in several Capcom-developed games.

We are testing in DX11 mode.

Lost Planet 2 is one of the newest Direct X 11 games on the market and our results show another great result for the CrossfireX XFX HD5850 cards, scoring around 65 fps average. This is around 10 fps slower than the GTX 460 SLI solution, but interestingly the minimum frame rate is around 3 fps higher which actually has slightly more impact on the gameplay smoothness.

The single HD6850 card performs around the same level as the HD5870, with slightly better minimum frame rate results.

Mafia II is a gritty drama which chronicles the rise of World War II veteran Vito Scaletta, the son of Sicilian immigrants. As the game progresses, Vito will join the Falcone Crime Family and become a made man. There are 15 chapters in the game, connected into one storyline.

We tested at 1080p with fullscreen: on, antialiasing:on , Anisotrophic filtering: 16x, Shadow Quality: High, Ambient Occlusion: on, Geometry Detail: High and APEX PhysX: off.

The XFX HD5850 in Crossfire delivers results 4 frames higher than the GTX460 reference clocked solution in SLi. The single HD6850 performs around the same levels as the eVGA GTX460 768mb superclocked edition, scoring around 5 frames per second higher in the minimum zone. Mafia 2 runs very well on both AMD and nVidia products.

The makers of Metro 2033 – 4A Games was founded by people who split off from GSC Game World a year before the release of S.T.A.L.K.E.R.: Shadow of Chernobyl, in particular Oles’ Shiskovtsov and Aleksandr Maksimchuk, the programmers who worked on the development of X-Ray engine used in the S.T.A.L.K.E.R. series. The game utilizes multi-platform 4A Engine, running on Xbox 360, PlayStation 3, and Microsoft Windows. There is some contention regarding whether the engine is based on the pre-release X-Ray engine (as claimed by Sergiy Grygorovych, the founder of GSC Game World, as well as users who have seen the 4A Engine SDK screenshots, citing visual similarities, shared resources, and technical evaluation of the pre-release 4A Engine demo conducted at the request of GSC Game World), or whether the engine is an original development (as claimed by 4A Games and Oles’ Shiskovtsov in particular, who claims it would have been impractical to retrofit the X-ray engine with console support). 4A Engine features Nvidia PhysX support, enhanced AI, and a console SDK for Xbox 360. The PC version includes exclusive features such as DirectX 11 support and has been described as “a love letter to PC gamers” because of the developers’ choice to “make the PC version [especially] phenomenal”.

We tested at 1920×1080 with settings on default ‘normal’

Metro 2033 is a taxing engine which demands high performance levels to run effectively at our choosen settings. The XFX HD6850 in Crossfire delivers around 63 fps, 2 fps less than the eVGA GTX460 FTW, which works out at £25 per lost frame if we factor in market prices today. The reference clocked GTX460 SLi falls 4 frames behind the XFX HD5850 cards.

The single XFX HD5850 card delivers similar performance to the MSI GTX460 Talon edition at 810 core, which is remarkable.

Resident Evil 5, known in Japan as Biohazard 5, is a survival horror third-person shooter video game developed and published by Capcom. The game is the seventh installment in the Resident Evil survival horror series, and was released on March 5, 2009 in Japan and on March 13, 2009 in North America and Europe for the PlayStation 3 and Xbox 360. A Windows version of the game was released on September 15, 2009 in North America, September 17 in Japan and September 18 in Europe. Resident Evil 5 revolves around Chris Redfield and Sheva Alomar as they investigate a terrorist threat in Kijuju, a fictional town in Africa.

Within its first three weeks of release, the game sold over 2 million units worldwide and became the best-selling game of the franchise in the United Kingdom. As of December, 2009, Resident Evil 5 has sold 5.3 million copies worldwide since launch, becoming the best selling Resident Evil game ever made.

When paired in Crossfire, the HD6850's push out a staggering 108 frames per second average, falling just slightly behind the GTX460 SLI solution. The single £155 HD6850 falls in line with the last generation HD5850 … not bad considering the HD5850 cost £250 when initially released.

Tom Clancy HAWX is set in the same universe as Tom Clancy’s Ghost Recon Advanced Warfighter; as Captain Scott Mitchell, the Ghost leader, is featured in a few missions of the missions. Plot elements are carried over from other Tom Clancy games such as the missile defense system found in Tom Clancy’s EndWar. G4′s interview with H.A.W.X’s lead designer Thomas Simon reveals that the game takes place in between Tom Clancy’s Ghost Recon Advanced Warfighter 2 and Tom Clancy’s EndWar.

The player begins the game in 2014 as the player assumes the role of former U.S. Air Force pilot, David Crenshaw, who is part of an elite unit called H.A.W.X (“High Altitude Warfare eXperimental squadron”), provides fire-support missions for the Ghost team carrying out covert operations in Ciudad Juárez, Mexico. However, shortly after the mission, the Air Force decides to deactivate the H.A.W.X squadron and its pilots, including Crenshaw, are recruited into the PMC Artemis Global Security.

We are testing : DX 10.1 with shadows high, sun shafts high, ambient occlusion (SSAO) very high. view distance high, forest high, environment high, texture quality high, HDR on, Engine heat on and DOF on.

The XFX HD6850 and GTX460 are really closely matched with this engine with both reference clocked dual card solutions delivering around 120 frames per second average. The single HD6850 is closely matched with the HD5850 scoring around 70 frames per second.

Distributed Computing Technologies Inc. (Distributed.net) is a worldwide distributed computing effort that is attempting to solve large scale compute-intensive projects, by utilizing the combined idle processing cycles of member computers.

RC5-72 is a security-based encryption key project and is a competition to test the security and strength of 72-bit RC5 encryption keys. Packets are fetched from the server via the client, the cruncher tests each packet block of keys and sends the data back to the server. User statistics are logged on the stats server.

Great results with this test for the 6800 architecture.

This new GPU tool, called TessMark, is small synthetic graphics benchmark focused on one of the main features of Direct3D 11 and OpenGL 4 capable cards, focusing on GPU tessellation.

Like Unigine Heaven, TessMark allows to select the level of tessellation. The small difference is that TessMark offers four different levels

• moderate = tessellation factor of 8
• normal = tessellation factor of 16
• extreme = tessellation factor of 32
• insane = tessellation factor of 64

Moderate and normal levels are levels we’ll find in real world applications like games. Extreme and insane levels are not really realistic ‘real world’ tests. We are using the normal settings today.

We were surprised to see such staggering performance from the reference and overclocked GTX460 hardware. We spoke with Jerome from Geeks3d.com who said that ‘TessMark is focused only on the tessellation engine of the DX11 graphics cards’.

AMD told us that this benchmark doesn’t mirror a ‘real game’ situation at all, but we felt it would be interesting to include, even if it isn’t a real world style benchmark.

ShaderToyMark is an OpenGL benchmark, developed with GeeXLab, and focused on pixel shaders only.  ShaderToyMark? is a WebGL tool for testing GLSL shaders. Shadertoy utilises several of these shaders running at the same time in the same 3D window.

The contributors of Shader Toy are all famous demomakers and their shaders are real gems. It’s just amazing to see what can clever people do with some sin/cos and other math tricks. ShaderToyMark can be seen as a modest tribute to their fantastic and sometime unreal work.

Unfortunately Shadertoy doesn't work properly in Crossfire or Sli, meaning we need to use single card statistics. The findings are close, the XFX HD6850 is only 9 points behind the reference clocked GTX460.

HQV Benchmark 2.0 is an updated version of the original tool and it consists of various video clips and test patterns which are designed to evalute motion correction, de-interlacing, decoding, noise reduction, detail enhancement and film cadence detection.

There are two versions of the program, standard definition on DVD and high definition on Bluray. As our audience will be concentrating on HD content so will we.

This has a total of 39 video tests which is increased from 23 in the original and the scoring is also up from a total of 130 to 210. As hardware and software gets more complicated, the software has been tuned to make sure we can thoroughly maximise our analysis.

Read our initial analysis over here.

	XFX HD6850
Dial	4
Dial with static pattern	5
Gray Bars	5
Violin	5
Stadium 2:2	5
Stadium 3:2	5
Horizontal Text Scroll	5
Vertical Text Scroll	5
Transition to 3:2 Lock	5
Transition to 2:2 Lock	0
2:2:2:4 24 FPS DVCAM Video	5
2:3:3:2 24 FPS DVCam Video	5
3:2:3:2:2 24 FOS Vari-Speed	5
5:5 FPS Animation	5
6:4 12 FPS Animation	5
8:7 8 FPS Animation	5
Interlace Chroma Problem (ICP)	5
Chroma Upsampling Error (CUE)	5
Random Noise: Sailboat	5
Random Noise: Flower	5
Random Noise: Sunrise	5
Random Noise: Harbour Night	5
Scrolling Text	5
Roller Coaster	5
Ferris Wheel	5
Bridge Traffic	5
Text Pattern/ Scrolling Text	5
Roller Coaster	5
Ferris Wheel	5
Bridge Traffic	5
Luminance Frequency Bands	5
Chrominance Frequency Bands	5
Vanishing Text	5
Resolution Enhancement	15
Theme Park	5
Driftwood	5
Ferris Wheel	5
Skin Tones	7
Total	196

The image quality with Catalyst 10.10 is the best yet, as the driftwood test scores 5 now instead of 2 points, bringing the total to 196 points.

To test power consumption today we are using a Keithley Integra unit and we measure power consumption from the VGA card inputs, not the system wide drain. The best way to get maximum load results is by using Furmark, and even though it is not indicative of a real world situation it shows the limits the card can theoretically demand. The ‘gaming’ results are measured when playing Crysis Warhead and is a more valuable result to take from this.

The XFX HD6850 is a very efficient card requiring just over 100 watts when gaming and 130 watts under Furmark extended load. In Crossfire expect to be using around 200 watts when playing an intensive game such as Crysis.

The tests were performed in a controlled air conditioned room with temperatures maintained at a constant 25c – a comfortable environment for the majority of people reading this.

Idle temperatures were measured after sitting at the desktop for 30 minutes. Load measurements were acquired by playing Crysis Warhead for 30 minutes and measuring the peak temperature. We also have included Furmark results, recording maximum temperatures throughout a 30 minute stress test. All fan settings were left on automatic.

The customised solution on the XFX HD6850 delivers great results, with a maximum peak around 60c when gaming. Furmark pushes the core 9c higher, although the fan is very moderately paced, more on this shortly.

Return to ambient is a feature we have recently added to our reviews … we measure the time it takes for a solution to return to idle temperatures, immediately after full load. The faster the time, the better the cooler – for example a Noctua NH D14 cooler will return an Intel processor to idle temperatures much faster than a reference cooler. This is a good indication of how quickly a heatsink can dissipate heat.

The cooling solution on the XFX board is very capable, returning to idle in around 15 seconds.

Recently we have changed our method of measuring noise levels. We have built a system inside a Lian Li chassis with no case fans and have used a fanless cooler on our CPU. We are using a heatpipe based passive power supply and an Intel SSD to keep noise levels to a minimum. The motherboard is also passively cooled. This gives us a build with completely passive cooling and it means we can measure noise of just the graphics card inside the system when we run looped 3dMark tests. Ambient noise in the room is around 20-25dBa. We measure from a distance of around 1 meter from the chassis and 4 foot from the ground to mirror a real world situation.

Why do this? Well this means we can eliminate secondary noise pollution in the test room and concentrate on only the video card. It also brings us slightly closer to industry standards, such as DIN 45635.

KitGuru noise guide
10dBA – Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA – High Quality Computer fan
40dBA – A Bubbling Brook, or a Refridgerator
50dBA – Normal Conversation
60dBA – Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA – City Traffic or a Garbage Disposal
90dBA – Motorcycle or Lawnmower
100dBA – MP3 player at maximum output
110dBA – Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet takeoff/Gunshot (close range)
160dBA – Instant Perforation of eardrum

The custom cooler is relatively quiet when gaming, hovering between 32 dBa and 34 dBa. Under Furmark testing this rose a little after 10 minutes of extended load to around 36.6dBa.

Unfortunately when using the Catalyst Control Center we are limited to 850mhz and we wanted to try and push the card further. We therefore decided to try the new beta of the Sapphire TriXX software which worked great, even allowing us to increase voltage to 1300.

Our initial overclocking session without increasing the core voltage ended up with a 860mhz limitation, so we raised the voltage to the maximum.

By increasing the voltage we were able to achieve 950mhz on both cores and 1133mhz on the memory which is a staggering result!

XFX has another winner on its hands with this custom-cooled Radeon HD 6850. The product looks fantastic and the performance levels for such a modest asking price are astounding. Initially we had been informed of a price close to £155 inc vat, but – just before we went to publication – XFX informed us that Scan in the UK will be offering this card for £135 inc vat.

The attractive XFX cooler, with large offset fan, is a very capable design delivering responsive return to idle times while remaining quiet, even under extended load.

On a performance level the XFX HD6850 is closely matched to a reference clocked GTX460, losing in some games and winning in others … but always competitive.

When we got around to overclocking we were astounded to see that using Sapphire's beta TriXX overclocking software, we managed to push the core to 950MHz, the same speed as the Sapphire HD6850 we tested. While these overclocks could be lower when future yields hit retail, we would assume that 900MHz is a realistic figure when taking tolerances into consideration. Once this card is overclocked, the performance goes into a whole new playing field. Holding its own against a card costing about £40 more is some feat.

We can think of no reason not to buy the XFX HD6850 – the custom cooler is excellent, the performance is great ‘out of the box' and amazing if you spend time with voltage and clock increases, its just a shame XFX don't supply a tool similar to Sapphire's TriXX.

KitGuru says: If you've ever wanted to own a supercar for the price of a family saloon – then the Radeon HD 6850 is the answer. It's great straight out of the box. The turbo charger kicks in when you overclock it and it's nothing short of stunning in CrossFireX formation. No wonder nVidia has been dropping the price of the Fermi cards in response: Against the Radeon HD6850, discounting seems to be the only reaction possible.

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