Two vs. Three: Zotac GeForce 9800 GX2 Against 3-Way CrossFire ATI Radeon HD 3870

ATI Radeon HD 3870 X2 didn’t remain the 3D King for long: Nvidia regained the initiative by launching their new GeForce 9800 GX2. However, AMD graphics division still has something to respond with: a graphics subsystem with three ATI Radeon HD 3870 chips. Will ATI 3-way CrossFireX platform be able to compete successfully against Nvidia GeForce 9800 GX2? We are going to answer this question in our today’s review!

by Alexey Stepin , Yaroslav Lyssenko
04/04/2008 | 12:18 PM

A little while ago AMD’s graphics department took the palm of technological supremacy from Nvidia’s hands releasing the ATI Radeon HD 3870 X2 graphics card. Combining two RV670 cores on one PCB, this was the fastest single-card graphics solution that delivered higher performance than Nvidia’s best single-chip cards, GeForce 8800 GTS 512MB and GeForce 8800 GTX, even though not in every game. In our review we noted that the $449 card had a huge potential that was yet to be untapped. If ATI’s programmers did their job right, that card would soon become the best choice for a demanding gamer.


The ATI Radeon HD 3870 X2 was not destined to become the true king of the 3D world, though. It only reigned until the announcement of Nvidia’s dual-processor GeForce 9800 GX2. This card couldn’t be an absolute champion due to the inherent drawbacks of the homogeneous multi-processor architecture, but it did beat the Radeon HD 3870 X2 where SLI technology worked just because the G92 was superior to the RV670. It’s like the single GeForce 8800 GTS 512MB beating the Radeon HD 3870. That is not a big problem because these solutions belong to different market sectors: the GeForce 9800 GX2 is more advanced and, accordingly, more expensive. Its release makes AMD a pursuer again, just like it had been pursuing Nvidia for a long time before the arrival of the Radeon HD 3870 X2. This also limits the user’s choice in the high-end category (over $599/$649).

The ATI CrossFire technology allows building asymmetric 3-way systems like ATI Radeon HD 3870 X2 + ATI Radeon HD 3870. For comparison, the current implementation of Nvidia SLI supports only symmetrical configurations, including the configuration with three identical graphics cards. Thus, ATI adherents have got a means to compete with the Nvidia GeForce 9800 GX2: you can buy a single Radeon HD 3870 in addition to your ATI Radeon HD 3870 X2 and enable 3-way CrossFireX mode. Having a combined price of about $640 ($449+$189), such a system could make a rival to the single GeForce 9800 GX2 whose price varies from $599 to $649. Of course, you’ll need an appropriate mainboard with two PCI Express x16 slots and CrossFire support, but purchasing one is not a problem today. There are a lot of mainboards based on Intel’s and AMD’s chipsets providing the required capabilities.

This review will show you how competitive ATI’s 3-way CrossFireX system is against the Nvidia GeForce 9800 GX2. The latter will be represented by the Zotac GeForce 9800 GX2 graphics card.

Zotac: New Name of Old Acquaintance

Zotac is a new name on the consumer hardware market. Most users will hardly know anything about the company or its reputation (which is yet to be earned).

Despite the obscure name, Zotac is backed up by PC Partner Group, a mainboard maker who has a hand in Sapphire Technologies, the major supplier of Radeon-based graphics cards. In fact, PC Partner uses the Zotac brand to promote graphics cards and mainboards based on Nvidia’s solutions.

Established in 2006, Zotac International (MCO) Limited introduced its first products in March 2007. The company’s product range wasn’t wide at first, getting little attention from the press, but now it offers more products and even two exclusive graphics card series: AMP! with pre-overclocked frequencies and Zone with passive cooling. Zotac’s mainboards are based only on Nvidia’s reference designs as yet.

Today, PC Partner owns 40 surface-mounting lines and employs 6000 workers and a team of 130 engineers. Considering such advanced manufacturing facilities and human resources, Zotac can be expected to show an aggressive market behavior.

PC Partner owns but a part of Sapphire Technologies while Zotac belongs to it entirely. Thus, PC Partner is more interested in the successful development of this new brand.

Let’s see how Zotac appeals to the potential customer.

Package and Accessories

The Zotac GeForce 9800 GX2 comes into retail in a standard box that easily fits into an ordinary plastic bag. The box is quite originally designed in lively yellow-orange-and-gold colors.

It looks aesthetic enough. The face side of the box tells you the key specs of the graphics card. You should know, however, that the caption about the card’s having 1GB of onboard memory is somewhat misleading. The GeForce 9800 GX2 has two GPUs, which means two memory banks, 512MB each. Due to architectural reasons, 3D applications can only access 512 megabytes of memory. The promise of a low noise level is not true, either. The GeForce 9800 GX2 is rather noisy under load.

Inside the thin wrapper, there is the main cardboard box. It is filled with foam rubber in which compartments are cut out for the graphics card and its accessories. Thus, the card is securely protected against possible damage during transportation or storage. Besides it, there are the following accessories in the box:

The accessories are not gorgeous, yet the manufacturer took care about the user including even an adapter for the 8-pin power connector if your PSU doesn’t offer an appropriate plug. It’s also nice to see a 2m HDMI cable in the box. It would cost you up to $40 if purchased separately. The user manual contains just the basic info about the installation of the card, but that should be enough for a majority of gamers.

Besides everything else, the box contains a copy of Lost: Via Domus also known as Lost: The Video Game. The game is based on the highly popular TV series. You play the role of amnesia-ridden Elliott Maslow, a character who was not seen in the original series, and you have to remember your past and find the way to escape from the mysterious island. The game doesn’t feature exceptional visuals or an outstanding gameplay, yet it is a top-class title indeed. The popularity of the original TV series plays into Zotac’s hand, too.

The packaging and accessories of the Zotac GeForce 9800 GX2 deserve our praises. The card is securely packaged and is accompanied with every accessory necessary including a couple of nice bonuses, a copy of Lost: The Video Game and a HDMI cable. Unfortunately, like many other manufacturers, Zotac does not include a software player for Blu-ray and HD-DVD movies although the decoding and post-processing of high-definition video is a strong point of the G92 processor and the GeForce 9800 GTX card.

Design and Specifications

The GeForce 9800 GX2 features a very complex design, and it’s no wonder that the new graphics card is covered by Nvidia’s no-modifications prohibition. Unique single-PCB versions of this graphics card may come out in the future, though. For example, we expect ASUS to attempt such an experiment. But right now, all versions of GeForce 9800 GX2, including the described product from Zotac, are copies of the reference card.

As opposed to the Nvidia GeForce 7950 GX2, the PCBs of the GeForce 9800 GX2 face each other and allow using a common heatsink for both graphics cores. The PCBs are about 27 centimeters long, the GeForce 9800 GX2 having roughly the same dimensions as the GeForce 8800 GTX/Ultra. The cooler’s fan is located between the PCBs, and there is a figured hole in each of them fir air intake. The bottom PCB, equipped with a PCI Express x16 connector, carries a PCI Express switch. The PCBs are fastened together with metallic poles and connected with two flexible cables.

Each PCB is equipped with a three-phase GPU power circuit governed by a Volterra VT1165MF controller and a memory power circuit based on an Intersil ISL6269CRZ. The bottom PCB has a standard 6-pin PCI Express 1.0 connector while the top one is equipped with an 8-pin PCI Express 2.0 connector. The card doesn’t start up if you plug a 6-pin power cable into the latter connector, reporting a power error. Nvidia took this precaution because the top PCB cannot access the PCI Express x16 slot and is powered only from the external connector while the power consumption of the components it carries is surely above 75W. Well, you can also use the included adapter (2x6-pin PCI Express → 1x8-pin PCI Express) to power the card up. This is safe electronically because the splitting of the PSU’s +12V power rail into multiple output lines is only done to limit the current in order to comply with safety regulations, and six pins is quite enough for a current of about 8A. This is the load of the top PCB of the GeForce 9800 GX2 by our estimates. The power connectors are placed rather inconveniently: the connector locks press against each other, and you have to use a screwdriver to take them out. Moreover, the narrow slits in the casing make it impossible to plug in connectors with large locks. An SPDIF connector is located nearby.

The GPUs of the Zotac GeForce 9800 GX2 have a standard configuration with 128 ALUs, 32 (64) TMUs and 16 ROPs. The frequencies are standard: 600MHz for the main domain and 1500MHz for the shader domain. Nvidia doesn’t allow overclocking the GeForce 9800 GX2 even at the factory, obviously due to high heat dissipation. Each PCB carries eight GDDR3 chips (Samsung K4J52324QE-BJ1A) with a rated frequency of 1000 (2000) MHz. That’s indeed the frequency the chips are clocked at by the card. 3D application can access 512 megabytes of memory, so the mention of 1024 megabytes is just a marketing trick.

The Zotac GeForce 9800 GX2 has the same interfaces as the reference card: two dual-link DVI-I ports and one HDMI port. There are two LEDs there, one of which reports that the card is powered properly and the other marks the Master DVI port in Quad SLI mode. To configure the latter mode, the card offers a MIO connector for connecting to another GeForce 9800 GX2. As we noted earlier, the card supports multi-monitor configuration only if SLI is disabled.

The cooling system is simple and consists of a heatsink between the PCBs – it has contact with the GPU dies via copper soles. Most of the card’s mounting bracket is populated with interface connectors, and most of the hot air is exhausted into the system case through the slits in the cooler’s casing. The small opening in the bracket seems to serve an aesthetic purpose as it is highlighted with bright green LEDs. The airflow through this hole is very weak.

The cooler is almost silent in 2D mode, but the fan speed is increased greatly under load and there is more noise then. The card becomes perfectly audible even in a closed system case. We guess the ATI Radeon HD 2900 XT is the only modern graphics card that has a nosier reference cooler. So, this cooler does its job all right, but at the expense of the user’s acoustic comfort.

Temperature, Overclockability, Compatibility

Our attempt to overclock the Zotac GeForce 9800 GX2 was almost as successful as with the Gainward Bliss 9800 GX2 1024MB. We made sure the GPUs of this sample of GeForce 9800 GX2 were stable at 700MHz. The ALU frequency grew from 1500 to 1725MHz at that. The memory chips were overclocked from 1000 (2000) to 1100 (2200) MHz.

In our Chieftec LCX-1 system case with a 120mm fan on the back panel and a closed side panel, the GPU temperature was 93-95°C under load. That’s why we recommend you to be careful if you are going to overclock your GeForce 9800 GX2. Nvidia reduced the clock rates of the new card relative to the GeForce 8800 GTS 512MB because the GeForce 9800 GX2 is very hot even at its default clock rates and overclocking may lead to overhead.

We didn’t observe serious incompatibility of the Zotac card with mainboards, but it did refuse to start up on our Intel Desktop Board D925XCV. So, the card may be incompatible with some mainboards based on old chipsets like Intel’s 915/925 series. That’s not a big problem, though, as the GeForce 9800 GX2 is unlikely to be installed into an old system.

Testbed and Methods

To test the gaming performance of Zotac GeForce 9800 GX2 and ATI 3-way CrossFireX we put together the following testbeds:

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 - Adaptive Anti-Aliasing/Multi-sampling for ATI Catalyst and Antialiasing – Transparency: Multisampling for Nvidia ForceWare. As a result, our ATI and Nvidia driver settings looked as follows:

ATI Catalyst:

Nvidia ForceWare:

For our tests we used the following games and synthetic benchmarks:

First-Person 3D Shooters

Third-Person 3D Shooters



Synthetic Benchmarks

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 in any way. 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 Zotac GeForce 9800 GX2 we have also included the results for the following single graphics accelerators and ATI 3-way CrossFireX systems:

We put together an ATI 3-way CrossFireX system by combining ATI Radeon HD 3870 X2 with a single ATI Radeon HD 3870 graphics card.

The tests were performed in the following resolutions: 1600x1200, 1920x1200 and 2560x1600. If the game didn’t support 16:10 display format, we set the last resolutions to 1920x1440 and 2048x1536 respectively. We decided to give up testing in 1280x1024 this time, because it is hardly of any interest to those gamers who can afford a GeForce 9800 GX2 or 3-way CrossFireX configuration.

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 anisotropic filtering 16x as well as MSAA 4x antialiasing. 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.

Performance in First-Person 3D Shooters

Battlefield 2142

This game doesn’t support display resolutions of 16:10 format, so we use resolutions of 1920x1440 and 2048x1536 pixels (4:3 format) instead of 1920x1200 and 2560x1600 for it.

The 3-way CrossFireX system is slightly ahead of the Zotac GeForce 9800 GX2 at every resolution, but the minimum speed fluctuates greatly at 2048x1536. The opponents deliver about the same level of gaming comfort, so the choice depends on your personal preferences. The Zotac card has one advantage, though. It needs only one PCI Express x16 slot.


BioShock doesn’t support FSAA when running in Windows Vista’s DirectX 10 environment. That’s why we benchmarked the cards without FSAA.

Again, the two graphics subsystems are roughly similar, the ATI one being somewhat superior in terms of minimum speed. Anyway, the Zotac GeForce 9800 GX2 allows playing comfortably at every resolution including the yet-exotic 2560x1600. So, the user’s choice will depend on the retail prices of the products and the availability of a mainboard supporting ATI CrossFire technology.

Call of Juarez

The in-game benchmarking tools do not support 2560x1600 resolution, and we had to limit our test to 1920x1200.

Nvidia’s solutions have problems with memory management and ATI’s 3-way configuration enjoys a tremendous advantage. Its performance fluctuates rather too much at resolutions above 1280x1024, making the gameplay not quite comfortable while the Zotac GeForce 9800 GX2 also delivers an acceptable speed at 1280x1024.

Call of Duty 4: Modern Warfare

CrossFireX technology doesn’t work well here. It brings about no performance benefits with two GPUs and results in a performance hit with more GPUs. That’s a fault of the software part of the system which, according to ATI/AMD itself, does not support OpenGL applications as yet.

The scalability problem of CrossFireX technology is not due to the game engine or the principles of modern multi-GPU systems because the Zotac GeForce 9800 GX2 delivers superb performance, allowing to play this game even at 2560x1600 with 4x FSAA.


This game is tested at the High level of detail except for the Shader option which is set at Very High. Thus we try to hit the balance between image quality and performance.

The CrossFireX system doesn’t scale up much when there are more than two GPUs in it: the software support is still deficient. The Zotac GeForce 9800 GX2 feels all right providing a high average frame rate at resolutions up to 1920x1200 inclusive. The minimum speed is only 10-11fps, though, which means slowdowns and jerkiness.

Enemy Territory: Quake Wars

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.

The current implementation of CrossFireX doesn’t support over two GPUs in OpenGL applications. But while a quad-processor system with two Radeon HD 3870 X2 cards is not slower than one such card, the 3-way CrossFire configuration is inferior to one dual-processor card from ATI. You should better disable CrossFireX mode unless you want to have a dangerously low speed even at 1600x1200.

The Zotac GeForce 9800 GX2 has no such problems and delivers superb performance even at 2560x1600. So this graphics card carries on the long-time tradition that Nvidia’s cards suit better for running OpenGL applications.

Half-Life 2: Episode Two

The 3-way CrossFire system is somewhat faster than the Zotac GeForce 9800 GX2 at 1600x1200 and 1920x1200. The latter outperforms the opponent by 11-12% at 2560x1600, though.

Both solutions look equal in this test if you don’t count such factors as the number of slots they take and the level of power consumption.

S.T.A.L.K.E.R.: Shadow of Chernobyl

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.

Nvidia’s solutions have always been strong in this game, and the Zotac GeForce 9800 GX2 confirms this point once again. The 3-way CrossFireX platform is not a failure, though. It ensures good results at resolutions up to 1920x1200 inclusive. It can only not be used for the yet-exotic 2560x1600 mode.

Performance in Third-Person 3D Shooters

Lost Planet: Extreme Condition

Unfortunately, inadequate software optimizations do not allow the 3-way CrossFireX system show a competitive result. On the other hand, the Zotac GeForce 9800 GX2 delivers comfortable performance at 1600x1200, which is very good considering how demanding this application is at the highest graphics quality settings.

Tomb Raider: Legend

Both systems suffer a performance hit relative to the corresponding single graphics cards. However, the Zotac GeForce 9800 GX2 is somewhat better. Although it is slower than the single GeForce 8800 GTS 512MB, it still allows playing with enabled FSAA at every resolution, save for 2560x1600.

Performance in RPG

Hellgate: London

Despite the good results, the Zotac GeForce 9800 GX2 cannot be used for Hellgate due to the flickering of the image in SLI mode. You can disable this mode and use the card as a GeForce 8800 GTS 512MB with appropriate performance. A for the 3-way CrossFireX platform, the system just hung up as soon as the game menu was loaded. Let’s wait for the updates of the Catalyst and ForceWare drivers.

The Elder Scrolls IV: Oblivion

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.

As we noted in our previous report, ATI’s CrossFireX technology for more than two GPUs behaves oddly in TES IV, having big fluctuations of minimum performance in closed environments and a small performance reduction relative to the single Radeon HD 3870 X2. The Zotac GeForce 9800 GX2 is immaculate in comparison.

It’s different in the open scenes: ATI’s multi-GPU systems take the lead, and it is the Zotac GeForce 9800 GX2 that has a low minimum speed now, only 20fps at 1920x1200. The 3-way CrossFireX platform makes the game playable even at 2560x1600. So, the two opponents seem to end this round of our test session with a draw.

Performance in Strategies

Company of Heroes: Opposing Fronts

The new add-on to Company of Heroes is tested in DirectX 10 mode only since it provides the highest quality of the visuals.

Alas, this is one of those cases when both parties are on the losing side. The 3-way CrossFireX system provides no advantage in comparison with the single Radeon HD 3870 X2 whereas the Zotac GeForce 9800 GX2 has a very low minimum of speed. As a result, the Radeon HD 3870 X2 remains the best choice as it offers full playing comfort at 1280x1024 and even fast enough for playing at 1600x1200/1680x1050.

Command & Conquer 3: Tiberium Wars

The game having a frame rate limiter, you should consider the minimum speed of the cards in the first place.

The Zotac GeForce 9800 GX2 and the 3-way CrossFireX are both good at resolutions up to 1920x1200 inclusive. Their maximum speed is below 24fps at 2560x1600 but the game seems to be playable anyway.

World in Conflict

ATI’s 3-way configuration works correctly, making up for the failure of the single Radeon HD 3870 X2, but that’s not enough to provide comfortable playing conditions. The Zotac GeForce 9800 GX2 performs somewhat better, but it is barely ahead of the GeForce 8800 GTS 512MB.

The average frame rate varying from 12 to 20fps, the mentioned solutions cannot be used for running World in Conflict at the highest settings.

Performance in Synthetic Benchmarks

Futuremark 3DMark05

The 3-way CrossFireX system has a better score than the Zotac GeForce 9800 GX2, but the overall 3DMark05 score has little practical worth for modern top-performance graphics cards.

In the first test the Zotac card enjoys a small victory in the 2560x1600 mode. At the lower resolutions the 3-way system from ATI is no worse then Nvidia’s solution although has fewer TMUs (48 against 64).

The second test only shows a difference between the cards in the 2560x1600 mode. This time the ATI system is on top, being superior to Nvidia’s solution in sheer computing power.

The results of the third test are roughly similar to the first one, but the Zotac GeForce 9800 GX2 enjoys a bigger lead over the 3-way CrossFireX system here. This only refers to 2560x1600 resolution – the two solutions are similar in the other modes.

Futuremark 3DMark06

The Zotac GeForce 9800 GX2 is 6-7% behind the 3-way CrossFireX platform, just like in 3DMark05, but 3DMark06 provides more detailed information about performance of modern graphics cards. Let’s see.

Strangely enough, it is in the SM2.0 tests that the Zotac GeForce 9800 GX2 is the farthest from the leader despite the advantage in the amount of TMUs. Something prevents it from performing properly as its result is almost no different from the ordinary GeForce 8800 GTS 512MB. We can’t explain this behavior.

The 3-way CrossFireX platform wins the SM3.0/HDR tests with a smaller lead. These tests make extensive use of the GPU’s computing capacities, and RV670-based solutions are unrivalled yet in this respect.

The first test is similar to what we’ve seen in 3DMark05, but the Zotac GeForce 9800 GX2 takes the lead sooner, at 1920x1200, due to the increased complexity of the scene. At 2560x1500 it is two times as fast as its opponent. Nvidia’s solution wins in the second test, but with a smaller advantage at 2560x1600.

It’s just the opposite in the SM3.0/HDR tests: the 3-way CrossFireX platform wins both of them. It’s only in the 2560x1600 resolution of the first test that the Zotac GeForce 9800 GX2 is competitive against the 3-way system from ATI. The latter enjoys a bigger advantage in the second test which puts a lower load on the texture processors.


Summing up our today’s tests, we can say that after a year’s break, ATI has finally entered the same price category with Nvidia introducing its 3-way CrossFireX system that is competitive to the GeForce 9800 GX2 at least theoretically. Is it competitive in practice, though? The following table can give you the answer:

Obviously, it’s too early for ATI to claim a victory or even a tie: the Nvidia GeForce 9800 GX2 is faster in most of the tests. The ATI platform won five out of the 18 tests including both versions of 3DMark. In three more tests, it equaled Nvidia’s result. Not so bad, considering how difficult it is to support the triple-processor graphics subsystem on the software side and the lack of support for three GPUs in OpenGL applications. ATI is going to collaborate with game developers and polish off the software aspect of CrossFireX to solve these problems, but the user already has a choice.

The choice in favor of ATI’s CrossFireX requires a higher qualification from the user who has to deal with two individual graphics cards. It also means you must have a CrossFire-compatible mainboard with two PCI Express x16 slots. The power consumption and heat dissipation of this graphics subsystem are going to be high. In other words, the 3-way CrossFireX solution from ATI is inferior to the Nvidia GeForce 9800 GX2 in its consumer properties. The latter card has only one significant drawback – it doesn’t support multi-monitor configurations but Nvidia is expected to add such support soon. So, the user doesn’t seem to have a choice, after all.

We can’t recommend the 3-way CrossFireX as an alternative to the GeForce 9800 GX2 today. The triple-processor platform may only appeal to inveterate fans of the ATI brand. The GeForce 9800 GX2, although not an ideal solution, features higher performance and is much simpler to install and use.

As for the Zotac card we tested today, it is hard to say anything new about the card, because it is a precise copy of the reference GeForce 9800 GX2, which is the fastest single graphics card available today and the best choice for a wealthy gamer.

However, we would like to give Zotac due credit for taking good care of their users: Zotac included all the necessary adapters into the box as well as such nice bonuses as an HDMI cable and a full version of Lost: Via Domus game. The Zotac GeForce 9800 GX2 is a high-quality product. It’s not going to disappoint you if you are aware of the features peculiar to modern dual-processor graphics cards.