Product review: The AMD Radeon HD 3870 X2 - BeHardware
>> Graphics cards
Written by Damien Triolet
Published on January 28, 2008
Since the release of the GeForce 8800 GTX and even after its small update in the form of the Ultra, AMD has not been able to rival Nvidia for the top performance slot. Indeed Nvidia has a more performance efficient architecture and itís difficult for AMD to compete with that of its Radeon HD 2000 and 3000. On the other hand, the arrival of a mid-range high performance chip with lower power consumption and a relatively lower cost has enabled AMD to release a card equipped with 2 of these GPUs. Finally, this may give them some hope to take back first place.
CrossFireThe technology used for the functioning of this card is of course based on CrossFire which is now more mature. One small subtlety is that AMD opted for its software version which is already used on the entry level. This is in contrast with the "hardware" version which is generally used for the mid and high end and requires two CrossFire connections to create a bridge between the two cards.
The hardware methodís advantage is that it enables higher performances because the dedicated connection is used for the transfer of images from one card to the other. In Crossfire software this transfer takes place via the PCI Express bus and can therefore limit performances. So is there a lack of efficiency with the multi-GPU Radeon HD 3870 X2? Actually no, it does look promising (at least on paper) and this is something we are going to verify in the following pages.
So why the optimism? First of all, because there is a PCI Express switch on the PCB. Although limited to the 1.1 norm, it manages three 16x ports, one towards the system and one towards each GPU. This authorizes P2P transfer which means avoiding having to go through the chipset and consequently improving efficiency. Another and possibly more important point is related to Radeon HD 2000 and 3000 architecture. The PCI Express bus is a bus through which writing is executed and not reading. This consequently implies action on the part of the GPU which has to send its work to the other one. With an older GPU or a GeForce, the GPU is blocked when it is writing via the PCI Express bus. This means that it is unable to calculate a frame at the same time, signifying that transfers from one GPU to another in multi-GPU mode are a waste of calculation time which can be even greater in high resolution. However, if you recall the presentation of the Radeon HD 2900, AMD mentioned that they have integrated a dedicated processor for PCI Express bus management, which means that these cards do not suffer from this inconvenience.
The two RV670 GPUs and PLX PCI Express switch.
In the end, the main performance related weaknesses of CrossFire software disappear or are at least reduced. At the same time there is added flexibility because a single versatile connection is used instead of a higher performance solution that is dedicated and only limited to certain functions. This is a simplification which should prove beneficial in the long term and finally we donít find any negatives to the functioning of CrossFire software the way it was implemented on the Radeon HD 3870 X2.
Specifications, the card, power consumption
Thanks to its two GPUs at frequencies of 825 MHz, the Radeon HD 3870 X2 is the first graphic card to surpass a theoretical calculation power of 1 GFLOPS. On the other hand, compared to the Radeon HD 3870 its memory is set at a lower speed of 900 MHz instead of 1125 MHz. The fact that there is now two of everything allows doubling the memory bandwidth with the transition from 1 to 2 GPUs and gives the card this very high number. However, two Radeon HD 3870s in CrossFire have 25% more memory bandwidth.
Connect3D Radeon HD 3870 X2Connect3D was the first partner to be able to supply us with its Radeon HD 3870 X2. As is generally the case for this type of product itís identical to the reference card AMD provided us with :
The card is equipped with an imposing and heavy cooling system which explains the reinforced base on the underside. One of the GPU cooling blocs is in copper while the other is aluminum. Two 6 pin power connectors are required and there is an 8 pin conducive to the activation of Overdrive for overclocking via drivers.
Connect3D announces immediate availability at a price that should be around 399Ä for a classic bundle which is limited to various power and TV cables as well as DVI to VGA and HDMI converters.
Power consumption and noiseWe evaluated the power consumption of the different cards. Measurements were taken at the wall socket, in order to have the total power consumption of the power supply, in this case, an Enermax Galaxy 850W.
Use of the 55 nanometer process and PowerPlay in order to reduce consumption means the Radeon HD 3870 X2 doesnít blow measurements (too much) off the counter. AMD told us that in multi-GPU mode, it was too complex to completely deactivate one of the GPUs in stand-by and they had to only settle for PowerPlay to reduce consumption. In the end, the Radeon HD 3870 X2 consumes less than a GeForce 8800 Ultra in stand-by but more in load.
While the higher consumption in load isnít too logical given the power of this card, noise levels can be more of a problem for this type of product. In rest, the card is silent while in load itís another story. The fan constantly goes from low to very high speeds which turns out to be very annoying and even incomprehensible that AMD would approve of such a solution on its high end. We will have to look towards other models other than this reference one and hope to find more acceptable sound levels.
DriversImplementation inside drivers consists more or less of activating CrossFire while masking this option in order that this technologyís name is not exposed on platforms upon which its functioning with several graphic cards is not authorized. Of course, the Radeon HD 3870 X2 functions on all chipsets, including those from Nvidia which is something we checked.
However, itís unfortunate that there is no option which allows deactivating the multi-GPU mode. In other words, if there is a problem in a game or application, you won't be able to switch to a "safe" mode. We hope AMD will remedy this by giving us such a choice in the future.
A multi-screen configuration is functional with this card; however, it was impossible to read any HD-DVD in both VC-1 and h.264 as PowerDVD simply displayed a black screen. Itís a rather bothersome bug and we donít know if the acceleration of HD video playing is actually supported on this product.
Finally, note that with current drivers you cannot yet combine two Radeon HD 3870 X2s but apparently this will change very soon. It will then be possible to have a quad-CrossFire system or combine a Radeon HD 3870 X2 with a single Radeon HD 3870 for a tri-CrossFire configuration.
The testsIn this test, we used ten games, four of which support DirectX 10. Tests were carried out only in 1920x1200 as a lower resolution isnít generally suited for such a high end product. There was however another reason: a lack of time. In fact, AMD decided to delay the launch the day before it was scheduled and then told us a new driver would fix performance problems. The new driver arrived Friday afternoon before the launch which was scheduled for 6 AM Monday morning which meant having to redo all tests on the AMD cards. Of course they could have had better timing.
Anisotropic filtering and HDR were activated in all cases when available in the game. Finally, transparency/adaptive antialiasing were activated in multisampling mode.
Of course, all updates to Windows Vista relative to performance were installed.
ConfigurationIntel Core 2 Extreme QX6850
nForce 680i SLI EVGA
2 GB DDR2
Forceware 169.04 (169.28b for Crysis)
Catalyst 8.1 beta.
Enemy Territory : Quake Wars
Enemy Territory : Quake Wars
While Quake Wars is based on the Doom 3 engine, it has undergone some evolution such as megatexturing which facilitates the work of artists; however, there is the additional cost in terms of decoding and access to megatextures. In the end, Quake Wars is a little more resource heavy than Doom 3 or Quake 4.
We saved a demo in a sequence versus 4 bots. Given that artificial intelligence was not calculated in the timedemo, results were less affected by the CPU than in actual gameplay or at least in this case versus our bot adversaries.
All parameters were set to a maximum in the game including 16x anisotropic filtering. The patch 1.2 was used.
In this first game test, the Radeon HD 3870 in CrossFire is equivalent to the Radeon HD 3870 X2 and they largely dominate the other cards. The advantage is smaller once antialiasing 4x was activated.
Half Life 2 Episode 2
Half Life 2 Episode 2
Still based on the Source Engine, Half Life 2 Episode 2 doesnít really have anything new on the technological level. It simply optimizes and more heavily relies on the engineís capabilities, making the game more resource heavy than its previous versions. We carry out a demo with all game options set to a maximum including anisotropic filtering which is in 16x.
While the Radeon HD 3870 in CrossFire just manages to surpass the GeForce 8800 Ultra, the Radeon HD 3870 X2 has lower performances equal to those of the 8800 GT.
We carry out an identical movement and measure the framerate with fraps. The test was done in high quality, complete dynamic lighting, maximum details (anisotropic filtering 16x) and foliage shadows. S.T.A.L.K.E.R. uses an engine based on differed rendering, which is fundamentally incompatible with MSAA and makes the use of antialiasing impossible. A type of filtering of edges carried out with a shader can be activated but results are mixed. The 1.00004 patch is used.
Radeons are generally behind GeForce cards. However with multi-GPUs, performances increase substantially enabling the Radeon HD 3870 X2 as well as a CrossFire system to largely surpass all other solutions.
Rainbow Six : Vegas
Rainbow Six : Vegas
The first PC game based on the Unreal Engine 3.0, Rainbow Six : Vegas is still a very resource heavy game. We measure performances in the introductory scene. The HDR mode is activated as it is more or less obligatory as without it banding is very noticeable. Shadows are set to ďlowĒ because a higher quality in this domain lowers performance too much in certain areas.
Originally designed for the Xbox 360, this game seems to have a natural affinity for the Radeon HD which has a similar architecture to the game consoleís graphic chip. In addition, CrossFire allows almost doubling gains as the Unreal Engine 3.0 is particularly at ease with a multi-GPU system. The Radeon HD 3870 X2 gives it everything it has resulting in twice the performances of the GeForce 8800 Ultra and does 10% better than two Radeon HD 3870s in CrossFire.
The game does not support antialiasing but Nvidia has implemented it to drivers as it has done with Oblivion. This is contrary to AMD who unfortunately didnít make this effort.
We saved a specific movement in order for it to be always identical and the test reproducible. Of course, HDR was activated.
The Radeons really liked this game and the X2 largely surpasses Nvidia cards with 4x antialiasing. Without it, performances are limited by the CPU.
Colin McRae DIRT
Colin McRae DIRT
To test Colin McRaeĎs latest opus which is very resource heavy we carried out a well defined sequence in high quality mode. Note that the activation of antialiasing is highly recommended given the way menus are rendered and because post processing effects amplify aliasing. The patch 1.2 was used.
Performances are almost doubled in multi-GPU systems. This time CrossFire is slightly ahead of the Radeon HD 3870 X2, but both are clearly ahead of all other solutions tested here.
The first game based on the Unreal Engine 3.0 to support DirectX 10, Bioshock has great graphics even in DirectX 9 mode while it is less resource heavy than Rainbow Six : Vegas. We carry out a well defined sequence of movement with all options pushed to a maximum.
In DirectX 9 mode, the Radeon 3870 X2 isnít surpassed by CrossFire and it has a large lead on the GeForce 8800 Ultra.
Like with Rainbow Six : Vegas, Nvidia allows the activation of antialiasing for this game which doesnít normally support it while AMD doesnít offer this option.
In DirectX 10 mode, performances improve significantly with the latest driver provided by AMD. This allows a single Radeon HD 3870 to nudge its way next to the GeForce 8800 GTX. On the other hand, with multi-GPUs performance gains are less than with DirectX 9. Nonetheless, it is still enough for the Radeon HD 3870 X2 to be ahead of all Nvidia cards.
Note that it is not yet possible to activate antialiasing in DirectX 10 mode for Nvidia and AMD.
Company of Heroes
Company of Heroes
Given that Company of Heroes received a DirectX 10 patch that adds a real plus on the graphics level, we decided to add it to our test protocol. All graphic settings were pushed to a maximum except for terrain details which remained on High (Ultra mode is reserved for DirectX 10). Textures were also limited to High, because the game indicates a lack of system memory for the GeForce in DirectX 9 mode with Ultra textures.
We run the integrated test on version 1.71.
With this game, the multi-GPU is largely to the benefit of performances placing the Radeon HD 3870 X2 in the lead; however, once again this advantage is reduced once antialiasing is activated.
In DirectX 10, strangely only one of the two GPUs of the Radeon HD 3870 X2 seemed to function without antialiasing which put it very far behind. "Hardware" CrossFire does not have this problem. With antialiasing, the new arrival does better and is equivalent to the GeForce 8800 Ultra.
World in Conflict
World in Conflict
Very resource heavy and with nice graphics, itís only natural World in Conflict joins our test suite. We carry out the internal test with the patch 1.0002. All game options are pushed to a maximum.
CrossFire suffers from a bothersome bug in World in Conflict. Text is scrambled which made navigation impossible in menus and therefore the execution of tests. This isnít the case with software CrossFire and the Radeon HD 3870 X2 does very well, easily surpassing all Nvidia cards (at least without antialiasing which otherwise kills its performances).
All cards do slightly less well in DirectX 10 mode. A bug for the Radeon HD 3870 X2 with antialiasing seems to make only one GPU function. This isnít the case for CrossFire.
Of course we canít forget Crysis and it was tested with its 1.1 patch (optimized for multi-GPU systems) as well as the latest drivers specific to this patch, Forceware 169.28b and the Catalyst 8.1 hotfix. We carried out the internal test in DirectX 9 High mode (forced via the addition of ĎíĖdx9íí behind the executable) and in DirectX 10 Very High.
While the Radeon HD 3870 X2 as well as the 2 Radeon HD 3870 take the lead without antialiasing, once activated, performances plummet and the GeForce 8800 GTX and Ultra hold a large advantage. The GeForce 8800 GT and GTS 512 are limited by their 512 MB memory.
With all details pushed to a maximum and in DirectX 10, CrossFire doesnít seem to be too efficient while the Radeon HD 3870 X2 does much better and takes the lead. Unfortunately, itís impossible to play in these conditions as the framerate is too low.
RecapAlthough individual game results are interesting, we calculated a performance index based on all tests with the same weight for each game. A score of 100 was given to the Radeon HD 3870 in 1920x1200.
On average the Radeon HD 3870 X2 has 26.5% higher performances than the GeForce 8800 Ultra, the fastest card up until now. This score gives an advantage to the new arrival compared to the CrossFire system which obtained a Ďí0íí in World in Conflict due to a bug which made the test impossible in DirectX 9.
With 4x antialiasing filtering activated, bugged ROPs in antialiasing with the Radeon HD 2000 and 3000 forced AMD to find an alternative solution that while it is very flexible limits performances. For this reason, the Radeon HD 3870 X2ís advantage in this area melts away and the card is only slightly ahead of the GeForce 8800 Ultra.
Note that results obtained in Rainbow Six : Vegas and Bioshock are not taken into account here because some cards arenít capable of supporting antialiasing in these games. Otherwise, you can consult a graph that includes this information in the final grade here.
In DirectX 10 and with antialiasing, there are bugs that penalize the Radeon HD 3870 X2 as much as the CrossFire configuration. On average, these two solutions are behind. Without antialiasing, results are better but the gap between them and the GeForce 8800 Ultra is small.
ConclusionWith the Radeon HD 3870 X2, AMD can finally and truly aspire to the top spot in terms of performances. Multi-GPU technologies are efficient and enable comfortable gains in most games. Thus on average, the Radeon HD 3870 X2 surpasses the GeForce 8800 Ultra. So is this the ultimate card for the demanding gamer? Unfortunately, no.
While multi-GPU technologies have indeed gained in maturity, they do not yet show the same level of robustness as mono-GPU systems do. There are still bugs which either affect performances, rendering quality, or simply make it impossible to launch the game. These problems arenít too frequent and the situation is improving but they do exist.
The list of disadvantages doesnít stop there. GPU performances are slightly limited by slower memory than mono-GPU versions which means that the card can occasionally lag behind a CrossFire system comprised of two Radeon HD 3870s.
Like all Radeon HD 2000 and 3000 card, there are reduced performances once antialiasing is activated. This is handicapping for a high end product often destined to function with high quality rendering that should include this filter.
The fact that we couldnít launch a single HD video was also problematic as this capability could not be evaluated and users will not be able to play their videos in the immediate future. We hope that AMD will find a remedy very quickly via new drivers.
What really bothered us the most with this new graphic card however was the noise level produced by its cooling system. In load speed brutally increases, comes back to normal and then starts over again. Why not a more stable intermediate speed? It was this large variation in noise levels that made it more noticeable and is something unacceptable on a high end product.
So should you forget about this card? We wouldnít go that far because it has a performance/price ratio that is largely more interesting than the GeForce 8800 GTX and Ultra. For 399Ä you will have the current highest performance solution with of course the few downsides mentioned above. In other words, itís reserved for the educated buyer that knows what they are getting into.
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