by Alexey Stepin , Yaroslav Lyssenko
09/11/2008 | 05:44 PM
The new Radeon HD 4800 X2 graphics card series proved that ATI had been right in placing its bet on multi-GPU technology. The senior model, Radeon HD 4870 X2, delivered superb performance in modern games, especially at a resolution of 2560x1600 pixels. Nvidia’s superiority that had been achieved by creating a 1.4-billion-transistor monolithic chip was lost in a moment.
It was not an easy victory for AMD/ATI, though. The two RV770 chips require a lot of power, and the new card has a power consumption of over 250 watts. This is an unprecedented level in the world of consumer 3D graphics hardware. The heat dissipation has grown up accordingly, so the Radeon HD 4870 X2 is not unlike a small room heater. Having a power consumption of 178 watts, the GeForce GTX 280 looks modest in comparison. But does Nvidia’s single-chip flagship have any reserves?
The G200 is tremendously complex. Coupled with the imperfect tech process, this limited the clock rates of the senior model of the GeForce GTX 200 series to 600MHz (main domain) and 1300MHz (shader domain). That’s not high for the year of 2008. For comparison, the previous-generation core, even in the 65nm version, was clocked at 678/1688MHz. Experiments show that the G92 core (GeForce 8800, 9800) can be stable at frequencies of 800/2000MHz and higher if you increase its voltage and provide enough cooling.
Without a doubt, the G200 must have some frequency reserves, too. And these reserves can be called for in order to compete with the Radeon HD 4870 X2.
This must be the reason why Zotac has released an overclocked version of GeForce GTX 280 in its AMP! series. Such pre-overclocked cards were expected because overclocking is in fact the only way of marketing a unique G200-based card. We don’t think any maker will release a GeForce GTX 280 with a unique PCB design because developing a PCB with a 512-bit memory bus is quite a daunting task.
So, today we will be testing the Zotac GeForce GTX 280 AMP! in games to see how an overclocked G200 compares with two RV770 cores combined.
The graphics card comes in an upright-oriented box of standard size. It is painted black, yellow and orange. The warm colors please the eye, but the picture on the box is rather trivial, showing a dragon.
All the technical info the potential user may be interested in is listed on the front side of the box. Particularly, the card belongs to the AMP! series targeted at enthusiasts. Factory overclocking is the distinguishing feature of this series. There is a sticker on the box, informing you of a copy of Race Driver: GRID included with the card.
The packaging quality is high as is typical of Zotac. The contents are laid into cut-outs in the layers of foam rubber that protect the card and accessories against any misfortune during transportation and storage. The card comes with the following accessories:
There is everything you need to use every feature of the Zotac GeForce GTX 280 AMP! including both types of power adapters. The only problem is that there is no software for playing HD video, but most of ATI’s and Nvidia’s partners do not include such software with their products. Besides, the GeForce GTX 280 is a gaming rather than multimedia card. It will connect to an LCD panel via HDMI easily, though. A DVI adapter and a cable for the sound card’s S/PDIF output are included for that.
The included game is a car simulator, a rather unusual choice. We had expected to find a first- or third-person shooter. Race Driver: GRID was announced in early summer. Although it doesn’t use DirectX 10 features, it boasts good visuals, an engaging gameplay, and positive reports from leading reviewers. That’s a real gift for everyone who likes racing.
So, our overall impression from the packaging and accessories of the Zotac GeForce GTX 280 AMP! are positive. The picture on the box might be more original, and there might be a software HD video player in the box, but instead you get a copy of a good car simulator. This is a gaming card after all.
All GeForce GTX 280/260 cards are copies of the reference samples, so there is no need to describe their design again. We already did this in our review of the theoretical aspects of Nvidia’s new architecture. Of course, the Zotac card is no different than others.
The single difference from the reference GeForce GTX 280 is the stickers on the cooler’s casing. The card is 27 centimeters long. ATI’s new flagship solutions are just as long as that, but the reasons differ: Nvidia’s card is long because of the 512-bit memory bus while ATI’s, because of the two GPUs. Anyway, you may have problems installing such long cards into a small system case.
Being a copy of the reference card, the Zotac has a seven-phase power circuit governed by a popular Volterra VT1165MF controller. One 6-pin and one 8-pin connectors are used for external power supply. You have to connect an 8-pin power cable or the card won’t start up, reporting a problem with a red LED. It is rather easy to bypass this protection, but we wouldn’t recommend you to do so. Even without the factory overclocking the load on the 8-pin connector is higher than the maximum allowable load for the 6-pin connector (75 watts). It is going to be even higher on the Zotac card which claims to be the fastest GeForce GTX 280 with air cooling. You will see that shortly. The memory power circuit is based on a Richtek RT9259A and receives power from the appropriate section of the PCI Express x16 slot.
The GeForce GTX 280 features a 512-bit memory bus, so there are two times more seats for GDDR3 memory chips in comparison with the traditional 256-bit designs. There are 8 chips on each side of the PCB (Hynix H5RS5223CFR-N2C, 512Mb, 16Mb x 32, 2.05V). They are rated for a frequency of 1200 (2400) MHz. The memory frequency is increased relative to the reference GeForce GTX 280: 1150 (2300) MHz as opposed to 1100 (2200) MHz. The memory bandwidth is thus increased from 140.8 to 147.2GBps. That’s not much. This can hardly affect the performance of the Zotac GeForce 280 AMP! in games, especially as the available memory bandwidth is hardly utilized fully by G200-based solutions.
The A2-revision G200 core is in its full configuration here: 240 unified shader processors, 80 texture processors and 32 raster back-ends. The GPU clock rates are increased relative to the reference card. The main GPU domain is clocked at 700MHz rather than at 602MHz while the shader domain frequency is increased from 1296 to 1400MHz. As opposed to the memory subsystem, the overclocked GPU makes a promise of a considerable performance growth in games that make wide use of the GPU’s computing resources. We estimate this performance growth at 5% to 12% but the gaming tests will show the precise numbers. Due to the complexity of the G200 chip, its display controllers are located in a separate chip called NVIO2. Nvidia used the same solution earlier with the G80 chip.
The graphics card offers two dual-link DVI-I ports and a universal 7-pin port for analog video output (YPbPr, S-Video, Composite). This sample of the GeForce GTX 280 doesn’t support DisplayPort, which would require a special translator chip. The HDMI interface is supported by means of a DVI-I → HDMI adapter (included into the box). You can enable audio-over-HDMI by connecting to the sound card’s S/PDIF output (the G200 chip doesn’t have an integrated audio core) using the included cable. The two MIO connectors covered with a rubber cap allow to join together up to three GeForce GTX 280 AMP! cards into a triple-SLI subsystem. Theoretically, such a subsystem is expected to deliver record-breaking performance. We’ll check out in an upcoming review if it really does. What we are sure of already, a triple-SLI subsystem is going to have a terrific power draw. We guess it would make a 1000W power supply a necessity.
The described card is equipped with the reference cooler whose design hasn’t changed much since the GeForce 8800 GTX. The changes have been evolutionary. Particularly, the cooler now has a larger heatsink. The metallic casing works as a heat-spreader, too. Still, the card is very hot. You just can’t take it into your hand for a few minutes after you have shut down the system.
A copper heat exchanger takes the heat off the GPU. It is connected to the heatsink with heat pipes that ensure uniform distribution of heat. Dark-gray thermal grease is used as a thermal interface. The memory chips, NVIO chip, and load-bearing elements of the power circuit are cooled by the cooler’s aluminum frame – it has juts at the appropriate places. Traditional fabric pads soaked in white thermal grease are used as a thermal interface for these components. The memory chips on the reverse side of the PCB are cooled by the back half of the cooler’s casing. It is fastened to the front half of the casing with 10 screws and a few latches, so the card is actually within a single massive metallic shell. The only protruding details are the mounting bracket and the PCI Express x16 slot. This monolithic thing ensures good heat transfer and protects the card’s components from damage but it also makes the card rather heavy. You must fix the mounting bracket in the case properly. Otherwise the card may damage the PCI Express slot.
The heatsink is cooled with a Delta blower we are familiar with by other reference coolers from Nvidia. This blower is nearly silent at low speeds but audible at high speeds. It has a lot of work to do on the GeForce GTX 280 because there is as much as 170 watts of heat to dissipate even on the reference card whereas the Zotac version is going to generate even more heat. Zotac’s stickers are glued to the cooler’s casing and fan. That’s the only way of making a GeForce GTX 200 different from other vendors’ products.
The Zotac GeForce GTX 280 AMP! works at increased frequencies, so it is interesting to see how higher its power consumption is in comparison with the reference card. We measured this on a 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. The Peak 2D mode was emulated by means of the 2D Transparent Windows test from PCMark05. This test is important as Windows Vista’s Aero interface uses 3D features. Here are the results:
Click to enlarge
As expected, the power consumption is the same in the 2D and Peak 2D modes because every GeForce GTX 200 drops its GPU and memory frequencies to 100MHz in 2D mode. In the 3D mode the Zotac card consumes 15W more than the reference sample. Well, even this result is modest in comparison with the Radeon HD 4870 X2.
We measured the amount of noise produced by the Zotac with a Velleman DVM1326 noise-level meter and found it to be just as noisy as the reference card.
Unfortunately, our experience with the Zotac GeForce GTX 280 AMP! suggests that this card is prone to overheat, at least in hot weather. The GPU temperature reached a critical 105°C after two hours of our tests, triggering the protection system which reduced the GPU clock rates automatically. This resulted in a momentary pause, and then the game would go on normally or exit into the OS. Perhaps it is a problem of our particular sample, but you still must be aware that pre-overclocked versions of GeForce GTX 280 are subject to overheat. You must make sure you system case is ventilated well and is not too cramped. You may also need to adjust the speed of the card’s fan, for example with RivaTuner. This would increase the noise, especially in 3D mode, but modern top-end graphics cards with their extremely high power dissipation leave no other choice.
Now let’s see if the Zotac card can be competitive against the Radeon HD 4870 X2.
For our performance tests of Zotac GeForce GTX 280 AMP! 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 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 Zotac GeForce GTX 280 AMP! we have also included the following single graphics accelerators to participate in our test session:
Besides, we have also tested ATI Radeon HD 4870 CrossFire.
Since Zotac GeForce GTX 280 AMP! belongs to the top price range and theoretically can compete against ATI Radeon HD 4870 X2, 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.
Zotac’s factory overclocking has no effect in any of the tested resolutions, including 2560x1600. That’s not a surprise considering the modest system requirements of this game. The two versions of GeForce GTX 280 coincide up to a fraction of one frame-per-second.
BioShock doesn’t support FSAA when running in Windows Vista’s DirectX 10 environment. We benchmark graphics cards without FSAA in this game.
There is an effect from the factory overclocking of the GeForce GTX 280 in BioShock. It can be observed at resolutions up to 1600x1200. The performance growth is so high that the Zotac overtakes the Radeon HD 4870 X2. The latter wins the higher resolutions, though. Both cards have the same practical value at 1920x1200 but the Radeon HD 4870 X2 is unrivalled at 2560x1600. The Zotac card seems to encounter some fundamental limitations of the G200 architecture at the highest resolution because its average performance growth relative to the reference card is negligible, as opposed to the lower resolutions.
Call of Juarez does not support 2560x1600 resolution, so we have to limit our tests to 1920x1200.
The Zotac card shows a small increase in average performance, not higher than 10-11% at 1920x1200. This is not enough to catch up with the ATI Radeon HD 4870 X2 which ensures a comfortable average and near-comfortable bottom speed at 1920x1200.
The Radeon HD 4870 X2 is challenged in three out of the four tested resolutions. The Zotac is especially brilliant at 2560x1600 which is the main battlefield for today’s top-end graphics solutions. This card also has lower power consumption and heat dissipation, which may be the decisive factor for some gamers.
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.
The overclocking is rewarding in Crysis, but the Zotac still can’t yield a bottom speed of 25fps or higher. Anyway, it is confidently ahead of the Radeon HD 4870 X2 at low resolutions and provides the best bottom speed at 1920x1200. That’s quite a good result overall.
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.
There is an effect from the overclocked frequencies of the Zotac card, but you can only see it at 1920x1200 and higher resolutions. The 10% increase in average performance at 2560x1600 is not enough to catch up with the Radeon HD 4870 X2 which has a combined memory bandwidth of over 200GBps.
Like in most of the previous tests, the performance growth is 10-11%, which is good considering the small frequency growth. Except for 2560x1600, this is enough for the Zotac card to compete with the Radeon HD 4870 X2. The choice is simple: if you need the highest performance possible, go for ATI’s solution. But if the latter’s power draw of 260 watts doesn’t sound good to you, you can buy the Zotac and have the same level of comfort at lower power consumption.
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.
The Zotac GeForce GTX 280 AMP! is as fast as the Radeon HD 4870 X2 but cannot win the test. ATI stands firm on the field where Nvidia used to be unrivalled. But you should keep it in mind that the Zotac requires less power, comes with a quieter cooler, and costs less than its opponent.
The Zotac is more than 15% ahead of the reference GeForce GTX 280 in some resolutions but it is only at 2560x1600 that it can match the Radeon HD 4870 X2. Unfortunately, this has no practical value because the frame rates are too low at that resolution.
Like in most other tests, the overclocking brings about an 8-10% increase in speed for the GeForce GTX 280. This is enough to outperform the Radeon HD 4870 X2 at the standard resolutions and overtake it in the less popular 2560x1600 mode.
The increased clock rates help the Zotac win the test at 1920x1200 but the Radeon HD 4870 X2 remains superior at 2560x1600. The Zotac has a somewhat higher bottom speed, though, which makes the cards equals in a gamer’s eyes in terms of performance.
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 Zotac is hardly any better than the reference card. You cannot feel this in practice considering the high frame rate of every card. The only real advantage over the Radeon HD 4870 X2 is that the Zotac has lower fluctuations of performance in open scenes at 2560x1600 but the reference GeForce GTX 280 can boast the same.
The new add-on to Company of Heroes is tested in DirectX 10 mode only since it provides the highest quality of the visuals.
The overclocked frequencies of the Zotac card increase its lead in the standard resolutions, but can’t help it overtake the Radeon HD 4870 X2 at 2560x1600. The latter delivers a twice higher bottom speed and thus makes the gameplay more comfortable. The difference can be felt subjectively.
This game has a frame rate limiter, so you should consider the minimum speed of the cards in the first place.
Command & Conquer 3 series games can’t be used as a benchmark for today’s top-end graphics cards because all of them deliver the same result. We’ll replace this test with something newer soon.
The Zotac GeForce GTX 280 AMP! can’t catch up with the Radeon HD 4870 X2 at 2560x1600. At the lower resolutions its performance is barely higher than that of the reference GeForce GTX 280.
It is only in the SM3.0/HDR tests that the Zotac shows higher performance than the reference card. There is almost no difference in the overall scores and in the SM2.0/HDR tests. This is logical since the SM3.0/HDR tests put an emphasis on the GPU’s computing resources.
When we enable 4x FSAA in the individual SM2.0 tests, we can see a difference of 4-6% between the reference GeForce GTX 280 and the overclocked version from Zotac.
The SM3.0/HDR tests agree with what we’ve seen above: the performance increase is higher at 7-12%. This confirmed the results of the gaming tests, indicating that the Zotac is about 10-11% faster than the reference card.
We minimize the CPU’s influence by using the Extreme profile (1920x1200, 4x FSAA and anisotropic filtering).
It is easy to see the benefits of the factory overclocking in 3DMark Vantage. The Zotac scores about 450 points or 10% more than the reference card.
The individual tests agree with the overall picture. The Zotac GeForce GTX 280 AMP! is 10-11% faster than the reference card, just like in the game tests.
Having tested the Zotac GeForce GTX 280 AMP! in all of our benchmarks, we can now answer the question how efficient the overclocking of a GeForce GTX 280 can be.
The maximum performance growth shown by the Zotac card is rather small at 10-12%. The average growth across all of the games is 8-10%. In some cases that was enough to make the Zotac card competitive to the Radeon HD 4870 X2 at resolutions up to 1920x1200 inclusive. Such games as Call of Juarez and Lost Planet were exceptions.
Even though ATI’s solution remained victorious at 2560x1600, with the few exceptions, people who are looking for the highest single-card graphics solution now have a wider choice.
The fact is the Radeon HD 4870 X2, with all its brilliance and numerous advantages, has a couple of considerable drawbacks. Easy to guess, we mean its power consumption and heat dissipation that are far higher than 200 watts. Some gamers just won’t like the idea of transforming their gaming computer into a source of heat, especially as electric power is getting ever more expensive. So, a factory-overclocked GeForce GTX 280 may indeed be more appealing than the Radeon HD 4870 X2, considering the comparable prices. Moreover, the Zotac card is going to be interesting for people who don’t have a 2560x1600 monitor. Although the Zotac is hotter and more voracious than the reference GeForce GTX 280, it is much more modest than the Radeon HD 4870 X2 in these parameters.
Included with the card are all the necessary accessories plus a copy of Race Driver: Grid. The only disappointment is the lack of software for playing HD video. We guess it is a drawback for a $400 product.
So, if you want the fastest graphics card available today, but do not like the Radeon HD 4870 X2 for some reason, the discussed card from Zotac is an option to consider. The Zotac GeForce GTX 280 AMP! won’t disappoint you unless you play at resolutions higher than 1920x1200.
For the highest performance and rich accessories bundle we decided to award Zotac GeForce GTX 280 AMP! Graphics card with our Editor’s Choice title as the fastest single-GPU graphics accelerator: