by Alexey Stepin , Yaroslav Lyssenko
09/15/2008 | 09:51 PM
The development strategy that focuses on high-performance mainstream graphics cards priced below $200 has proved its worth, but the question of having the world’s most advanced graphics solution is still important for both giants of the graphics hardware market. Such a solution serves to advertise the technical potential of the developer company. Today, the ATI Radeon HD 4870 X2 is the fastest graphics card available, but it relies on ATI CrossFireX technology in order to show its full potential. The Nvidia GeForce GTX 280, on its part, is the fastest among single-chip single-PCB graphics cards.
As we found out in our tests, the Radeon HD 4850 CrossFire subsystem can be a worthy opponent to the GeForce GTX 280, and ATI is expected to introduce a new Radeon HD X2 card with two 4850 chips to defeat Nvidia completely.
The value of a Radeon HD 4870 CrossFire subsystem as an independent solution could have only been high before the shipments of Radeon HD 4870 X2 and Nvidia’s subsequent price-cuts because its total cost is $600. Added to that is the cost of a CrossFire-supporting mainboard. However, adding a second Radeon HD 4870 to your existing one may be an option. Therefore testing a Radeon HD 4870 CrossFire configuration should present a practical interest to some users, and we are going to perform such testing using 15 popular games and two versions of Futuremark’s 3DMark.
We will also discuss the PCB design of the Radeon HD 4870 and of its cooling system as we didn’t do that in detail in our previous reports. We’ll also talk about the power consumption, noise and thermal parameters of this graphics card.
The ATI Radeon HD 4870 CrossFire will be built out of a Club 3D HD 4870 512MB GDDR5 and a VisionTek Radeon HD 4870 card. Both are copies of the reference sample from ATI but differ in packaging and accessories.
Club 3D products have always featured nice-looking packaging. The company’s designers prefer a noble and laconic style to gaudy colors and trivial pictures. And they succeed:
The matte black box looks stern, indicating an elite product. There are no decorations or anything. You can only see the model name and the company’s logo hinting that Club 3D is a recognized ace in its field. There is a minimum of technical info about the product. Detailed specifications together with a few promotional slogans can be seen on the back of the box.
There is a smaller black cardboard box inside the exterior package. It doesn’t offer any additional protection. The card is wrapped into an antistatic pack and lies in a cardboard tray. Below the tray you will find the following accessories:
That’s all actually. We didn’t even find a user manual or a CD with drivers! We only hope that ours was a presale copy of the card, which would explain the scanty accessories. The card just can’t be sold like that.
So, the packaging of this graphics card is designed but doesn’t offer any additional protection. The accessories are unsatisfactory. There are in fact no accessories at all especially if you compare this, for example, to the Sapphire HD 4850 512MB GDDR3 we reviewed earlier. The Radeon HD 4870 is a top-performance solution and must not be economized upon. The laconic design of the box is all right, but we don’t think this laconic style is any good with respect to the accessories.
The box with the VisionTek’s card is designed in an austere style, too. But unlike with the Club 3D product, it is more traditional: the front panel shows a picture of an alien resembling the Protoss race from StarCraft.
As a matter of fact, this creature comes from the sci-fi role-play game Mass Effect as is indicated by the sticker in the bottom right corner. Alas, it only says that the graphics card is an ideal choice for playing that game but the game itself is not included. The caption reporting the amount of graphics memory may remind you of the popular Call of Duty series of games but none of them can be found in the box either.
The packaging doesn’t offer any additional protection for the card. The latter is wrapped into an antistatic pack and lies in a cardboard tray within the smaller box. There is a compartment in that box that contains the following:
The accessories are no better than those of the Club 3D HD 4870. There is no user manual or CD with drivers, let alone any bonuses. Instead, there is an adapter for display devices that lack HDMI or VGA interfaces. You will hardly need it in the year of 2008.
Well, these accessories are not those you are going to receive with the off-the-shelf card. According to the manufacturer’s website, the box will contain at least a user manual and a disc with drivers. You will also probably get power adapters (Molex → 6-pin PCI Express) that will come in handy if your PSU has only one graphics card connector or no such connector at all.
Anyway, we guess the accessories to the card are only satisfactory. The potential customer may be misled by the mention of Mass Effect which is actually not included. The box design is nice and appealing but doesn’t match the nobleness of Club 3D’s design.
This section will make you amends for our not having discussed the design of the Radeon HD 4870 before. The PCB of the senior model is as large as the PCB of the Radeon HD 4850 but differs in wiring and component layout.
The card is largely covered with a massive dual-slot cooling system which makes the 4870 look not unlike the Radeon HD 2900. The card is shorter than the GeForce GTX 280, though. This is good because you won’t have problems installing your Radeon HD 4870 into small system cases. All the technical details we may be interested in are to be found under the cooler.
The power circuit is more sophisticated than on the junior model. This is logical since the GPU has a higher clock rate and higher power consumption. Instead of a single two-phase regulator, there is a three-phase one with an option of reinforcement by adding a fourth phase. This option would be redundant for a RV770 clocked at 750MHz, but may come in handy when designing PCBs for ATI’s next GPU.
The elements at the top edge of the PCB, particularly the two switching transistors and Pulse PA0511 inductors, constitute a two-phase voltage regulator for the memory chips. The whole power circuit deployed on the Radeon HD 4870 is based on a Volterra VT1165MF PWM-controller that had been used on both ATI’s (e.g. Radeon HD 3870 X2) and Nvidia’s (GeForce GTX 200) products. The voltage regulators work at a high frequency, so there are almost no electrolytic capacitors in the circuit. Such regulators are often referred to as “digital” but it is only the operating frequency that distinguishes them from their “analog” counterparts.
The card is equipped with two standard 6-pin PCI Express 1.0 power connectors that have a max load capacity of 75 watts. Considering the 55nm tech process and modest appetite of the RV770 chip, this should be quite enough. There is no need for an 8-pin PCI Express 2.0 connector which is rated for loads up to 150 watts.
We guess the most interesting thing about the Radeon HD 4870 is its GDDR5 memory. As opposed to GDDR3/4, GDDR5 can send or receive two 32-bit words per clock cycle, which doubles its effective frequency. Thus, GDDR5 chips working at a real frequency of 900MHz have an effective frequency of 3600MHz and appropriate bandwidth. GDDR5 has less strict requirements to the wiring than the previous memory types. Particularly, the routes do not have to be all the same length. This makes the PCB simpler and the graphics card, cheaper to make.
The Radeon HD 4870 carries eight Qimonda IDGV51-05A1F1C-40X chips with a capacity of 512Mb each (16Mb x 32). GDDR5 being not so particular about the wiring, the L-shaped positioning of the chips is okay. It helps simplify the PCB wiring even more in comparison with semicircular positioning.
The memory chips work at a voltage of 1.5V and have a rated frequency of 1GHz. For GDDR5 memory, this means an effective frequency of 4GHz. The memory frequency of the reference Radeon HD 4870 is set lower at 900 (3600) MHz, providing a memory bandwidth of 115.2GBps with a 256-bit memory bus. The results of gaming tests suggest that the Radeon HD 4850, let alone the senior model, does not feel any lack of memory bandwidth. Unfortunately, the total capacity of the local memory bank of both Radeon HD 4800 models is only 512 megabytes whereas a number of modern games can use more memory, especially at high resolutions. ATI’s solutions are inferior to the GeForce GTX 200 in this respect but the release of the Radeon HD 4870 should restore the balance.
The GPU marking is rather vague but it is clear that the memory controller is reprogrammed to support GDDR5. Many sources refer to this version of the chip as RV770 XT, which is not indicated by the marking yet helps distinguish versions of the RV770 chip set up for different graphics memory types. The GPU is clocked at 750MHz and incorporates 800 ALUs (grouped into 160 superscalar execution units), 40 texture processors and 16 render back-ends. The metallic frame on the packaging protects the die against chipping.
The left part of the PCB, near the connectors, is not very interesting. Most of it is just covered with a screen. There are no seats for additional chips because none is necessary. The DisplayPort interface is supported by the RV770 while analog video input is outdated. The card has two dual-link DVI-I ports (with support for resolutions up to 2560x1600), a 7-pin universal mini-DIN port, and two CrossFireX connectors for building multi-GPU subsystems out of as many as four Radeon HD 4870 cards. Of course, you’d need a mainboard with so many PCI Express x16 slots and a system case that can accommodate four dual-slot graphics cards. The audio-over-HDMI feature is supported by means of an appropriate adapter from ATI.
The cooling system of the Radeon HD 4870 resembles the cooler of the Radeon HD 2900 but there are considerable differences. The most important difference is that the heatsink is made from aluminum rather than copper. That’s reasonable since the RV770 generates less heat than the R600 while aluminum is cheaper and lighter than copper.
The cooler follows the classic design with a blower and the exhaust of the hot air out of the system case. The cooler has a copper sole contacting with the GPU die. A large heatsink consisting of thin aluminum plates locked together is connected to the sole by means of two thick heat pipes. The whole arrangement is not connected to the other parts of the cooling system. It is located within the casing and fastened to the PCB with four screws and an X-shaped spring-loaded back-plate. Traditional dark-gray thermal grease is employed as a thermal interface.
The bottom of the casing is made from aluminum and painted red. It is not connected to the heatsink or heat-exchanger but is fastened to the PCB individually with 10 screws. It is massive enough to serve as a heat-spreader for the memory chips and the load-bearing elements of the power circuit. Elastic thermal pads ensure proper heat transfer in the places of contact. The cooler uses a CF1275-B30H-C004 fan manufactured by NTK Technologies. Its max output power is 12 watts (1A at 12V), so you can imagine how noisy it can be. The fan has a four-pin connection with PWM-based speed management which has become traditional for modern graphics cards.
A red plastic casing is attached to the base. On the VisionTek card there is a sticker on the casing showing the same picture as on the product box. Club 3D just left the ordinary ATI Radeon logotype.
The cooler of the Radeon HD 4870 has a proper design. We have no doubt it is capable of dissipating 130 watts of heat at comfortable noise level.
We reported to you about the power consumption of the Radeon HD 4870 in an earlier review but didn’t publish the detailed data about the load on each of the power lines. Now we want to offer you these data as measured on our special testbed configured like follows:
The 3D load was created by means of the first SM3.0/HDR test from 3DMark06 running in a loop at 1600x1200 with 4x FSAA and 16x AF. Practice suggests it is a heavier load for the graphics card than the tests of 3DMark Vantage. The Peak 2D mode was emulated by means of the 2D Transparent Windows test from PCMark05. This test is important as it simulates the user’s working with application windows whereas Windows Vista’s Aero interface uses 3D features. Perhaps we’ll replace it with a HD video playback test which should be more interesting for the end-user. Here are the results:
As you can see, there is a good reason for the card to have two power connectors because their combined load is somewhat higher than the maximum permissible load for one 6-pin PCIe 1.0 connector, which is 75 watts. The numbers explain the necessity of an advanced dual-slot cooler. The Radeon HD 4870 is far from economical, even though it consumes less power than Nvidia’s newest solutions, especially GeForce GTX 280. The Radeon HD 4870 doesn’t have any special requirements to the PSU. Any high-quality 400-450W power supply will do. Of course, you need a higher-wattage PSU if you build a graphics subsystem out of two such graphics cards. We guess a 600W PSU should be enough. The only prerequisite is that the PSU had four graphics card connectors. Otherwise you’ll have to use adapters.
The reference Radeon HD 4870 is not cool at work. The GPU temperature is as high as 78°C when idle and 89-90°C under load. This may indicate some flaws in the cooler design, particularly the use of aluminum instead of copper, which make the Radeon HD 4870 rather noisy as you’ll see shortly. The samples of the card we dealt with were prone to overheat and reboot the driver. Hopefully, off-the-shelf samples will be free from this defect.
We measured the amount of noise produced by the card with a Velleman DVM1326 noise-level meter. We got the following results:
The Radeon HD 4870 is rather quiet in 2D mode, at least its noise is not irritating. The fan management system behaves oddly under load, speeding the fan up for a few seconds and then slowing it down again. This variation in noise level isn’t agreeable. Hopefully, the fan control algorithm will be corrected in the off-the-shelf cards because it is uncomfortable to use a Radeon HD 4870 when it sounds like this.
There are no compatibility issues. Like the junior model, the Radeon HD 4870 starts up on any mainboard irrespective of the version of PCI Express the latter supports.
For our performance tests of ATI Radeon HD 4870 CrossFire tandem we put together the following testbed:
According to our testing methodology, the drivers were set up to provide the highest possible quality of texture filtering and to minimize the effect of software optimizations used by default by both: AMD/ATI and Nvidia. Also, to ensure maximum image quality, we enabled transparent texture filtering. As a result, our ATI and Nvidia driver settings looked as follows:
For our tests we used the following games and synthetic benchmarks:
First-Person 3D Shooters
Third-Person 3D Shooters
We selected the highest possible level of detail in each game using standard tools provided by the game itself from the gaming menu. The games configuration files weren’t modified manually in any way, because the user doesn’t have to know how to do it. The only exception was Enemy Territory: Quake Wars game where we disabled the built-in fps rate limitation locked at 30fps. Games supporting DirectX 10 were tested in this particular mode.
Besides ATI Radeon HD 4870/4850 CrossFire we have also included the following single graphics accelerators to participate in our test session:
Since we are talking about the solutions from high-end market segment, we expanded the standard set of resolutions with 2560x1600 and 2048x1536, the latter for those games that do not support 16:10 aspect ratio. We used “eye candy” mode everywhere, where it was possible without disabling the HDR/Shader Model 3.0/Shader Model 4.0. Namely, we ran the tests with enabled MSAA 4x antialiasing and anisotropic filtering 16x in all tests except 3DMark. We enabled them from the game’s menu. If this was not possible, we forced them using the appropriate driver settings of ATI Catalyst and Nvidia ForceWare drivers.
Performance was measured with the games’ own tools and the original demos were recorded if possible. Otherwise, the performance was measured manually with Fraps utility version 2.9.1. We measured not only the average speed, but also the minimum speed of the cards where possible.
This game doesn’t support display resolutions of 16:10 format, so we use resolutions of 4:3 format instead.
This game is not a heavy test today, and the Radeon HD 4870 CrossFire just cannot show all its worth here. As a result, this subsystem is just somewhat faster than the CrossFire configuration with two Radeon HD 4860 cards. Of course, there is no difference between the 4870 X2 and the Radeon HD 4870 CrossFire.
The speed is high even at 2048x1536, so you may only be troubled by the tremendous power consumption and heat dissipation of this graphics subsystem, which is as high as 260 watts.
BioShock doesn’t support FSAA when running in Windows Vista’s DirectX 10 environment. We benchmark graphics cards without FSAA in this game.
CrossFire mode is not stable in most cases and doesn’t provide substantial performance benefits compared to the single card. In this case ATI Radeon HD 4870 CrossFire has enough resources to maintain comfortable performance at 2560x1600 where it doesn’t yield to the ATI/MD flagship solution.
Call of Juarez does not support 2560x1600 resolution, so we have to limit our tests to 1920x1200.
The Radeon HD 4870 CrossFire is a real breakthrough in this game as it ensures comfortable average and minimal speeds at resolutions above 1280x1024! You can play quite normally even at 1920x1200 because the occasional slowdowns to 19fps shouldn’t be much of a trouble. Interestingly, the pair of Radeon HD 4870 cards is faster than the Radeon HD 4870 X2.
This is a clear victory for ATI. Nvidia cannot do anything about that because its GPUs do not have such tremendous computing resources which are so demanded by this game.
Multi-GPU technology doesn’t work in this game, and the Radeon HD 4870 CrossFire is no faster than the single card whereas the 4870 X2 model delivers higher performance thanks to the larger amount of onboard memory.
Well, these solutions are still as fast as the GeForce GTX 280 at resolutions up to 1920x1200 inclusive. The single Radeon HD 4870 is only 15% slower than the more expensive card from Nvidia at 2560x1600 and provides a comfortable speed overall.
This game is tested at the High level of detail, excepting the Shaders option which is set at Very High. This way we try to achieve a compromise between image quality and speed.
There is no breakthrough in terms of performance because of the lack of graphics memory. The Radeon HD 4870 CrossFire configuration can only catch up with the GeForce 9800 GX2 at 1600x1200 and 1920x1200.
The Radeon HD 4870 X2 comes with two times more memory, so it can perform better in this visually astounding game. It is the leader at 2560x1600. On the other hand, the GeForce GTX 280 still ensures the highest bottom speed.
The frame rate is fixed at 30fps in this game as this is the rate at which the physical model is being updated at the server. Thus, this 30fps speed is the required minimum for playing the game.
Using extra-high-resolution textures, the game is sensitive to the graphics card’s memory bandwidth, so the Radeon HD 4870 CrossFire platform is more efficient than the Radeon HD 4850 CrossFire. However, the 4870 X2 model is far faster than the two Radeon HD 4870 cards at 2560x1600 due to the increased amount of onboard memory.
At resolutions above 1280x1024 the Radeon HD 4870 CrossFire is about as fast as the GeForce GTX 280 which has a 512-bit memory bus, and both deliver the same speed at 2560x1600. That’s a good but not impressive result considering the higher price and higher power consumption of the two Radeon HD 4870 cards.
The Radeon HD 4870 CrossFire wins this test, enjoying a 20% advantage over the GeForce GTX 280 at 2560x1600. There is no big difference between the Radeon HD 4870 CrossFire and the Radeon HD 4870 X2 in this test.
The game doesn’t support FSAA when you enable the dynamic lighting model, but loses much of its visual appeal with the static model. This is the reason why we benchmarked the cards in S.T.A.L.K.E.R. using anisotropic filtering only.
Although the game is optimized for Nvidia’s hardware, the Radeon HD 4870 CrossFire subsystem is in the lead across all the resolutions, including 2560x1600. The bottom speed is as high as 60fps at 1920x1200 and over 30fps at 2560x1600. The GeForce GTX 280 can’t achieve that.
Interestingly, the 4870 CrossFire configuration is far faster than the single-card flagship from AMD/ATI at 1600x1200 but not in any other resolution.
Alas, CrossFireX technology doesn’t show good scalability here. The 4870 CrossFire subsystem and the 4870 X2 card are hardly any better than the single Radeon HD 4870. You can see that the 4870 CrossFire is even slower than the single card at 2560x1600 (but not at the other resolutions) whereas the Radeon HD 4870 X2 is exactly as fast as the single-chip solution then.
Graphics subsystem with two Radeon HD 4870 graphics cards maintains slightly higher minimal fps rate, which means that Tomb Raider: Legend may be using additional onboard memory to its benefit. A pair of ATI Radeon HD 4870 cards as well as 4870 X2 model are slightly ahead of Nvidia GeForce GTX 280.
Although the Radeon HD 4870 CrossFire subsystem has a good average frame rate, the game is only playable at 1600x1200/1680x1050. At a resolution of 1920x1200 the speed is fluctuating wildly, occasionally dropping below 20fps. There are no such fluctuations with the Radeon HD 4870 X2, obviously due to the increased amount of graphics memory.
The CrossFire tandem lacks graphics memory to run the game at 2560x1600 whereas the graphics solutions with 896MB to 1GB of onboard memory deliver quite playable frame rates.
The game loses much of its visual appeal without HDR. Although some gamers argue that point, we think TES IV looks best with enabled FP HDR and test it in this mode.
The Radeon HD 4850 CrossFire reveals the full potential of this game, and the more advanced CrossFire configuration based on the Radeon HD 4870 cannot add anything to that. Unfortunately, both platforms have unpleasant fluctuations of speed in open scenes at 2560x1600, from a comfortable 68-72fps to an unacceptable 11-14fps. The Radeon HD 4870 X2 is better thanks to 1 gigabyte of memory available for each of its GPUs.
The new add-on to Company of Heroes is tested in DirectX 10 mode only since it provides the highest quality of the visuals.
CrossFire technology shows its effect at a resolution of 1600x1200 where it amounts to 18%. The performance gain is 25% at 1920x1200 but the bottom speed doesn’t grow up much. It is only at 2560x1600 that the Radeon HD 4870 CrossFire shows the efficiency we may expect from it, about 85%. Alas, the bottom speed is low. It is also low with the GeForce GTX 280 that has 80 texture processors and 1 gigabyte of graphics memory. The GeForces are faster than the Radeons at the lower resolutions, though.
Once again we can see that the Radeon HD 4870 X2 is better for playing at high resolutions than the pair of ordinary Radeon HD 4870 with 512MB of graphics memory.
The add-on to C&C 3: Tiberium Wars brought no changes into the technical aspect of the game. The game still having a frame rate limiter, you should consider the minimum speed of the cards in the first place.
The CrossFire platforms both reach the frame rate limit at 2560x1600 and provide a somewhat higher bottom speed in comparison with Nvidia’s solutions. This makes no practical difference, of course.
The Radeon HD 4870 CrossFire is again ahead of the Radeon HD 4870 X2 at every resolution, save for 2560x1600.
The Radeon HD 4870 CrossFire platform is not far better than the HD 4850 CrossFire in this test and did not manage to score 14,000 points. Interestingly, the Radeon HD 4870 X2 is worse than the CrossFire tandem here.
There is no difference between the graphics solutions in the SM2.0 tests despite the numerous textures and light sources. The CPU’s performance is obviously a limiting factor. In the more difficult SM3.0/HDR tests the Radeon HD 4870 tandem scores over 8,000 points, improving upon the results of the Radeon HD 4850 CrossFire.
It is the first time that an ATI solution takes first place in the first SM2.0 test. The gap is small, yet indicative of ATI’s ability to compete and beat Nvidia on the latter’s home turf. The second test depends on the graphics subsystem’s computing capabilities where the Radeon HD 4870 CrossFire knows no rival. It easily wins this test.
It is not quite clear why, but the tested CrossFire configuration boasts a performance growth of 30% relative to the Radeon HD 4850 tandem and 100% relative to the single Radeon HD 4870. In other words, CrossFire technology is at its maximum theoretical efficiency here! This impressive result is partly due to the high memory bandwidth of the 4870 CrossFire subsystem (over 200GBps) as well as to its 1600 ALUs and 80 texture processors clocked at 750MHz.
There is no notable advantage of the Radeon HD 4870 CrossFire over the Radeon HD 4850 CrossFire in this test. Fast memory doesn’t constitute an advantage here. The small difference in the results is a surprise because the former configuration has a 125MHz higher GPU frequency.
We minimize the CPU’s influence by using the Extreme profile (1920x1200, 4x FSAA and anisotropic filtering).
2 gigabytes of onboard memory are a factor, and the Radeon HD 4870 X2 performs better than the Radeon HD 4870 CrossFire.
Thanks to fast memory the Radeon HD 4870 CrossFire is superior in the first test, enjoying a 20% lead and leaving no chance to the GeForce GTX 280. The gap grows wider, to 35%, in the second test due to the higher efficiency of ATI’s texture processors that are also clocked at a much higher frequency than those of the Radeon HD 4850 CrossFire.
It is time to sum up our experience with the Radeon HD 4870 CrossFire subsystem. It has done well in our tests but could not compete with the Radeon HD 4870 X2 at the highest resolutions. However, the configuration with two Radeon HD 4870 cards is competitive at resolutions up to 1920x1200 inclusive.
Let’s view the detailed results using summary diagrams.
When you play in 1280x1024 resolution, the CrossFireX configuration is much slower than the GeForce GTX 280, by more than 20%, in only two games: Hellgate: London and CoH: Opposing Fronts. In both cases CrossFire technology doesn’t work at all, but the frame rate is sufficient for comfortable gaming in each of them. The CrossFireX configuration enjoys a substantial advantage in three tests, too. It amounts to 80% in Call of Juarez, ensuring the long-expected breakthrough in terms of playing comfort.
In four more games the ATI solution is ahead by 2% to 10%. That’s a good result but we shouldn’t forget that the GeForce GTX 280 is cheaper than the Radeon HD 4870 CrossFire ($499 against $600 for the graphics cards only).
There is almost no difference between the Radeon HD 4870 X2 and the 4870-based CrossFireX tandem here.
ATI’s platform shows its muscle at 1600x1200/1680x1050, beating the GeForce GTX 280 in five tests and slightly outperforming the latter in five tests more. There are cases when the 4870 X2 is ahead of the 4870-based CrossFireX and vice versa.
ATI’s dual-processor solutions are superior at high resolutions. They win 10 tests and have two ties against Nvidia’s four wins. The only drawback is the high power consumption and heat dissipation. Computer enthusiasts should upgrade their power supplies because the combined power draw of a dual-chip 4870-based system is over 250 watts!
It is at a resolution of 2560x1600 that the Radeon HD 4870 X2 is brilliant whereas the Radeon HD 4870 CrossFire is not, because it has only 512 megabytes of graphics memory. We guess two HD 4870 cards with 1GB of memory on each would behave exactly like the 4870 X2.
Anyway, the Radeon HD 4870 CrossFire beats the GeForce GTX 280 in nine tests and loses to it in only three out of 15 tests that support resolutions above 1920x1200. Moreover, the CrossFire tandem delivered a playable frame rate in most of the tests.
Summing it up, we guess that building a graphics subsystem out of two Radeon HD 4870 cards may make sense for people who already have one such card but do not have a 30-inch monitor with a resolution of 2560x1600. Moreover, the bulky 4870 X2 and GeForce GTX 280/260 may not be installed in small system cases and the Radeon HD 4870 may make a good alternative then.
Of course, the Radeon HD 4870 CrossFire subsystem is less easy to install than a single card. It also requires a mainboard with two PCI Express x16 slots and support for ATI CrossFire technology. But CrossFire is now supported by a huge number of mainboards based on AMD’s and Intel’s chipsets, so this shouldn’t be a problem.
The particular cards from Club 3D and VisionTek are precise copies of the reference sample and have all of its pros and cons. Unfortunately, both cards come with scanty accessories, which makes the less appealing in the customer’s eyes. We don’t think such economy is acceptable with regards to top-end solutions.