by Sergey Lepilov
05/04/2011 | 05:16 AM
Having launched its Barts-based Radeon HD 68xx series and Cayman-based Radeon HD 69xx series together with the dual-processor Radeon HD 6990, AMD now enjoys a strong position in the graphics card market. In the lower market segment the company has rolled out its Radeon HD 6790 that has a recommended price of $149 and is supposed to replace the Radeon HD 5770.
You will learn how fast, quiet and energy-efficient the new graphics card is from this review.
I’ve received a reference sample of AMD Radeon HD 6790 in OEM packaging. Let's take a look at it.
The Radeon HD 6790 is very much alike to Radeon HD 68xx series products and measures the same 249 x 99 x 36 millimeters. The card’s face side is covered by the cooler’s plastic casing that has a blower in its back part.
The dual-slot design seems to have already been adopted by affordable graphics cards as well. Some manufacturers offer single-slot Radeon HD 6850s, however, so I wouldn’t be surprised to see “slim” Radeon HD 6790s. There’s no aluminum plate on the reverse side of the PCB, which is good for cooling but makes you be more careful when installing or uninstalling the card.
The reference Radeon HD 6790 features a generous selection of outputs including two mini-DisplayPorts, two DVIs, and one HDMI (1.4a).
With so many connectors, the vent grid had to be made smaller. It is now but half the width of the second slot. Besides, some of the hot air remains inside the system case, passing through the three slits in the top part of the cooler's casing.
The AMD Radeon HD 6790 is equipped with two 6-pin power connectors. This is a downside compared to the Radeon HD 5770 which has only one such connector.
As you may guess, the new card has a healthy appetite for power. It is specified to consume up to 150 watts in 3D mode. This is more than required by the Radeon HD 5770 (108 watts) or by the Radeon HD 6850 (127 watts). The 2D consumption of all these cards is the same at 19 watts. The Radeon HD 6790 is also equipped with a connector for building dual-GPU CrossFireX configurations. You cannot unite three or four HD 6790s this way.
Here’s a photo of the card with its cooler removed:
You can see the elements of its four-phase power circuit in the front part of the PCB. The GPU is placed at an angle of 45 degrees.
The GPU die, manufactured on 40nm tech process, is the same size (255 sq. millimeters) and has the same transistor count (1.7 billion) as the GPUs of Radeon HD 68xx series products. Well, that’s because we’ve got a Barts LE chip here.
The GPU incorporates 800 shader processors, i.e. 160 processors less than in the Radeon HD 6850. The number of texture-mapping units is 40 (the HD 6850 has 48 TMUs). It is the raster operators that have been cut down most severely. There are only 16 ROPs here as opposed to the HD 6850's 32. AMD wants to make up for such a dramatic hardware modification by increasing the clock rate to 840 MHz, which is 65 MHz higher than the HD 6850's. The GPU voltage of our sample is 1.175 volts but we are not sure that off-the-shelf samples of this card are going to have the same voltage. The GPU’s voltage and clock rate are reduced to 0.9 volts and 100 MHz, respectively, in 2D applications.
The Radeon HD 6790 comes with 1 gigabyte of GDDR5 memory in 16 BGA-packaged chips installed on the face side of the PCB.
These are H5GQ1H24AFR T2C chips from Hynix. They have a voltage of 1.5 volts and a rated frequency of 5000 MHz. The graphics card’s memory frequency is actually 4200 MHz, so there are good overclocking opportunities. The frequency and voltage of the memory chips are reduced to 600 MHz and 1.35 volts in 2D mode. Most importantly, the memory bus is 256 bits wide, just like in the Radeon HD 68xx series, so the Radeon HD 6790 should have an advantage over the Radeon HD 5770 at high resolutions. Of course, this will only make a practical point if the card is able to deliver a playable frame rate at such resolutions.
The GPU-Z utility has the following to report about the Radeon HD 6790 graphics card:
Now let’s examine the card’s cooling system.
It represents a classic design consisting of a small aluminum heatsink with heat pipes for the GPU, a heatsink for the memory chips and power circuit components, a blower and a casing.
The heatsink on the Barts LE chip has three copper heat pipes, two of which are 6 millimeters in diameter and the third one is 8 millimeters in diameter. The pipes go out of the copper base which is 2 millimeters thick at its thinnest point.
There are slim aluminum fins soldered to the pipes. The fins are additionally soldered to the copper base. The heatsink isn't large but perhaps that’s quite enough for a Radeon HD 6790. We’ll check its efficiency out shortly.
The cooler is equipped with a 9.6W FD9238H12S blower from NTK (HK) Limited.
The blower’s speed is varied automatically within a range of 1200 to 4500 RPM.
In order to check out how hot the Radeon HD 6790 and other graphics cards included into this test session are, I ran the benchmark from Aliens vs. Predator (2010) in five cycles with maximum graphics quality settings (at 1920x1080 with 16x AF but without FSAA). It is at these settings that the GPUs had their highest temperatures. I used MSI Afterburner 2.2.0 beta 2 and GPU-Z version 0.5.3 as monitoring tools. Every test was carried out in a closed system case at an ambient temperature of 25°C.
The following diagrams show the temperature of the card with its fan controlled automatically (on the left) and at the maximum speed of the fan (on the right):
As you can see, the GPU is as hot as 76°C in the automatic mode, the fan working at up to 2040 RPM. This is not very loud, yet the card made itself heard in my rather quiet system case. At the maximum speed of the fan the Radeon HD 6790 is no hotter than 60°C but its fan is unbearably loud.
Unfortunately, my sample of Radeon HD 6790 wasn’t good in terms of overclocking. I could only increase the GPU clock rate to 910 MHz (+8.3%) and the memory clock rate to 4600 MHz (+9.5%) without having any stability issues or visual artifacts.
Hopefully, off-the-shelf samples of this card will have higher frequency potential.
Here’s the temperature of my overclocked Radeon HD 6790:
The top GPU temperature is now 80°C while the fan speed is 2170 RPM.
The AMD Radeon HD 6790 comes at a recommended price of $149. You can also spend the same money to buy an Nvidia GeForce GTX 550 Ti. The Radeon HD 5770, which is going to be eventually replaced by the new HD 6790, costs $20 less whereas the Radeon HD 6850, on its part, is $30 more expensive and costs $179. Nvidia's GeForce GTX 460 with 768 MB of memory can be had for about the same money whereas its faster version with 1024 MB of memory is somewhat more expensive. The junior version of GeForce GTX 460 has almost left the market and I couldn’t get one for this review. The rest of the mentioned cards will all be tested, though.
The graphics cards' specifications are listed in the following table:
I will give you a brief description of each card below. To make the review more interesting, I’ve collected products with nonstandard coolers and factory overclocking.
First goes MSI’s GeForce N460GTX Hawk:
This graphics card is equipped with an efficient cooler with heat pipes and features increased frequencies (811/1622/3900 MHz). However, I managed to overclock it further up to 875/1750/4600 MHz. I will benchmark it at both the default and the overclocked frequencies.
Here is the temperature of this card when running Aliens vs. Predator (2010):
The card isn’t very hot, the GPU temperature reaching only 62°C. However, the speed of its two 92mm fans is almost as high as 4000 RPM. Even though the monitoring tools cannot read the fans’ tachometer accurately, the card is subjectively very noisy.
The Radeon HD 6850 series is represented by a product from Hightech Information System Ltd. It is the Radeon HD 6850 IceQ X Turbo model.
This is a beautiful graphics card. It is a pleasure to take it into your hands and see it in your system case. Besides, the HIS Radeon HD 6850 IceQ X Turbo is 33 millimeters shorter than the reference Radeon HD 6850 and has only one rather than two power connectors.
The word Turbo in the product name indicates its pre-overclocked frequencies, which are 820/4400 MHz. My sample of the card proved to be able to speed up even further, up to 910/4880 MHz. This is higher than the frequencies of the reference Radeon HD 6870:
That’s a very rewarding result for overclocking.
The following diagrams show you the temperature of the overclocked card from HIS with its fan regulated automatically (left) or working at the maximum speed (right):
The peak GPU temperature is 69°C, the 92mm fan rotating at only 1900 RPM. That’s just an excellent result. At the maximum speed of the fan the GPU temperature is no higher than 59°C. Here is the BIOS of this superb graphics card!
Now we’ve reached the direct rival to the AMD Radeon HD 6790. The GeForce GTX 550 Ti series is represented by a Gainward product.
The GeForce GTX 550 Ti Golden Sample is Gainward’s new card with 1 gigabyte of onboard memory. The memory frequency is pre-overclocked by 300 MHz (+7.3%) to 4400 MHz whereas the GPU is clocked at 1000 MHz instead of the reference card’s 900 MHz (+11.1%). I could not overclock the GPU further but the memory chips were stable at 5100 MHz:
The simple cooler of this card, hailing from the very beginning of the 21st century, consists of a single aluminum heatsink and a slim 92mm fan. It copes with its job well enough, though. The GPU was only 78°C hot at a fan speed of 2370 RPM:
It is also going to be interesting to compare the new Radeon HD 6790 with the old Radeon HD 5770. I’ve got a reference sample of the latter card but installed a Deep Cool V4000 cooler on it:
I overclocked the sample from its default 850/4800 MHz to 965/1300 MHz:
The last graphics card in this review is a reference AMD Radeon HD 6870 which will serve as a reference point of the rest of the cards because it comes from the next performance and price category ($229).
Now that we’ve looked through the products to be tested, let's move on to the tests proper.
All graphics cards were benchmarked in a closed system case with the following configuration:
In order to lower the dependence of the graphics cards performance on the overall platform speed, I overclocked our 32 nm six-core CPU with the multiplier set at 25x and “Load-Line Calibration” (Level 2) enabled to 4.3GHz. The processor Vcore was increased to 1.3975V in the mainboard BIOS:
The 6 GB of system DDR3 memory worked at 1.72 GHz frequency with 8-8-8-16_1T timings and 1.64V voltage. Turbo Boost and Hyper-Threading technologies were disabled during our test session.
The test session started on April 16, 2011. All tests were performed in Microsoft Windows 7 Ultimate x64 with all critical updates as of that date and the following drivers:
The graphics cards were tested only in one resolution: 1920x1080. In our opinion, taking into account the current price of monitors supporting this resolution and an only 6~8 % performance difference between this resolution and 1680x1050, it doesn’t make much sense to add the latter to the tests. And higher resolutions aren’t for entry-level or mainstream graphics cards, anyway.
The tests were performed in two image quality modes: “Quality+AF16x” – default texturing quality with enabled 16x anisotropic filtering and “Quality+ AF16x+AA4(8)x” with enabled 16x anisotropic filtering and full screen 4x anti-aliasing (MSAA) or 8x if the average framerate was high enough for comfortable gaming experience. We enabled anisotropic filtering and full-screen anti-aliasing from the game settings or configuration files. If the corresponding options were missing, we changed these settings in the Control Panel of Catalyst and GeForce/ION drivers. There were no other changes in the driver settings.
The benchmarking games and applications list has two new names on it. They are Warhammer 40,000 Dawn of War II: Retribution and Crysis 2. Besides, some games were updated with new patches, and we recorded a new demo-scene in Left 4 Dead 2. As a result, the list had two popular semi-synthetic benchmarking suites, one technical demo and 19 games of various genres. Here is the complete list of tests used with the settings (all games listed in their release order):
If the game allowed recording the minimal fps readings, they were also added to the charts. We ran each game test or benchmark twice and took the best result for the diagrams, but only if the difference between them didn’t exceed 1%. If it did exceed 1%, we ran the tests at least one more time to achieve repeatability of results.
The graphics cards are sorted in the order of descending recommended price in two groups: at their default and overclocked frequencies. The results of the AMD Radeon HD 6870 are colored purple. AMD’s Radeon HD 6850, HD 6970 and HD 5770 are red; Nvidia’s GeForce GTX 460 and TX 550 Ti are green. Every card comes with 1 gigabyte of onboard memory, so this number is not indicated in the diagrams.
The 3DMark Vantage performance of the graphics cards is proportional to their recommended prices except for the FSAA-less mode (the Extreme profile) where the Radeon HD 6790 beats the GeForce GTX 550 Ti and the latter card cannot overtake the former when overclocked. Comparing the Radeon HD 6790 with the HD 5770 and HD 6850, the new card is halfway between its two cousins, filling in the previously unoccupied niche. Take note that the well-overclocked GeForce GTX 460 beats the more expensive Radeon HD 6870 in this benchmark.
The Radeon HD 6790 is ahead of the GeForce GTX 550 Ti in this version of 3DMark as well. The gap is over 20%. The new Radeon is again somewhere midway between the HD 5770 and HD 6850. When overclocked, the Radeon HD 6850 and GeForce GTX 460 get close to the reference Radeon HD 6870 but cannot overtake it.
This technical demo shows a strict correlation between performance and price. The Radeon HD 6790 enjoys a third win in the synthetic benchmarks in its competition with the GeForce GTX 550 Ti. Besides, the new card from AMD enjoys the biggest advantage over the Radeon HD 5770 across all the benchmarks and games. It amounts to 36-37%. The new Barts LE is obviously better at tessellation than the old Juniper XT. The Radeon HD 6790 is also 6 to 11% slower than the HD 6850, which is much smaller than the difference in their recommended prices.
As for the overclocked cards, the GeForce GTX 460 should be again noted for its being able to overtake the Radeon HD 6870. The overclocked HIS Radeon HD 6850 looks good, too.
Crysis doesn’t have anything new to tell us. The Radeon HD 6790 is still a little bit faster than the GeForce GTX 550 Ti and somewhere midway between the Radeon HD 5770 and HD 6850. The overclocked Radeon HD 6850 and GeForce GTX 460 deliver excellent performance, leaving the reference Radeon HD 6870 behind.
Far Cry 2 is the first but not the only game in which the GeForce GTX 550 Ti turns to be better than the Radeon HD 6790. The “green” card is 6 to 9% faster here. The Radeon HD 6790 in its turn is 9% ahead of the Radeon HD 5770 and 17 to 20% slower than the HD 6850. The overclocked GeForce GTX 460 delivers the highest frame rate in Far Cry 2 among the graphics cards tested for this review.
The Radeon HD 6790 outperforms the GeForce GTX 550 Ti in BattleForge: Lost Souls until 4x MSAA is turned on. Take note that neither of them delivers a playable frame rate. The Radeon HD 6870 wins this test. It cannot be challenged even by the well-overclocked Radeon HD 6850 and GeForce GTX 460.
We’ve got the same standings here as in the previous test: the Radeon HD 6790 is somewhat faster than the GeForce GTX 550 Ti in the FSAA-less mode but falls behind it as soon as FSAA is turned on. The Radeon HD 6790 is closer to the HD 5770 than to the HD 6850 in this game. The overclocked Radeon HD 6850 and GeForce GTX 460 are again ahead of the reference Radeon HD 6870.
AMD’s solutions are superior to their Nvidia opponents in this game. For example, the new Radeon HD 6790 competes with the more expensive GeForce GTX 460, leaving the similarly priced GeForce GTX 550 Ti behind by 18 to 37%. Moreover, even the Radeon HD 5770 proves to be able to beat the GeForce GTX 550 Ti, making it easy to choose the graphics card series for playing S.T.A.L.K.E.R. The overclocked Radeon HD 6850 and GeForce GTX 460 cannot outperform the reference Radeon HD 6870.
The “green” team are superior in the FSAA-less mode but fall behind their AMD opponents as soon as 4x MSAA is enabled. The Radeon HD 6790 is 16% faster than the Radeon HD 5770 and 17 to 22% slower than the Radeon HD 6850.
The Radeons are overall faster than the GeForce series cards in this test, the HD 6790 beating the GTX 550 Ti by 35%.
The performance of the graphics cards is again proportional to their recommended price except for the Radeon HD 6790 and GeForce GTX 550 Ti which cost the same money but differ in speed, the new card from AMD being 17-19% faster than its opponent.
Each of these graphics cards is downright slow in Metro 2033: The Last Refuge. Although this game runs at reduced graphics quality settings, we do not get a comfortable frame rate. We can only note that the Radeon HD 6790 is faster than the GeForce GTX 550 Ti.
The Radeon HD 6790 beats the GeForce GTX 550 Ti in Just Cause 2 in the FSAA-less mode. When FSAA is enabled, the Nvidia card is just as good as the AMD one. Besides, the new card isn’t much faster than the Radeon HD 5770 but as much as 16 to 26% slower than the Radeon HD 6850. The Radeon HD 6850 and GeForce GTX 460 are again comparable to the Radeon HD 6870 when overclocked.
The Radeon HD 6790 is ahead of the GeForce GTX 550 Ti by 17 to 20%, which is quite a lot considering that they come at the same recommended price. The HD 6790 is 10-14% faster than the HD 5770
Nvidia’s products are unrivalled in Lost Planet 2. The Radeon HD 6790 cannot match the GeForce GTX 550 Ti here, although the gap is rather small (4 to 10%).
The Radeon HD 6790 is as fast as the GeForce GTX 550 Ti in the FSAA-less mode but loses its ground as soon as FSAA is enabled. This is a peculiarity of the game engine.
The Radeon HD 6790 is again superior to the GeForce GTX 550 Ti, yet both are too slow for playing the game comfortably. The Radeon HD 6790 is also 2-6% ahead of the HD 5770 and 20-21% behind the HD 6850. So, the new card is not exactly midway between the two older products here. The Radeon HD 6870 stands out among the faster solutions although the overclocked HD 6850 and GTX 460 are but slightly slower.
The Radeon HD 6790 outperforms its closest market opponent in Civilization V by 9 to 19% depending on the graphics quality settings. It is also 16-19% faster than the HD 5770 and 12-13% slower than the HD 6850. The latter card is equal to the Radeon HD 6870 when overclocked.
We’ve got a different picture in F1 2010. The GeForce GTX 550 Ti is slower not only than the Radeon HD 6790 but also than the cheaper HD 5770. The GeForce GTX 460 is the only Nvidia solution to be competitive here, at least in the FSAA-less mode.
Nvidia’s solutions are overall better than their AMD counterparts in this game. The GTX 550 Ti is 11-13% faster than the Radeon HD 6790 and competes with the Radeon HD 6850 whereas the GTX 460 is only challenged by the more expensive Radeon HD 6870 in one out of the four test modes.
I used Adrenalin Crysis 2 Benchmark Tool 0.15 for this test.
I selected the Very High settings. The frame rate was not affected by any kind of antialiasing, so the diagrams show the results without 16x MSAA. I enabled anisotropic filtering in the driver’s control panel.
The Radeon HD 6790 is equal to the GeForce GTX 550 Ti in terms of average frame rate but has a somewhat higher bottom speed. These cards make the game more or less playable but I want to remind you that Crysis 2 does not support DirectX 11. The Radeon HD 6790 is 11% faster than the HD 5770 and 15% slower than the HD 6850. When overclocked, the latter card is close to the reference Radeon HD 6870, the overclocked GeForce GTX 460 winning this test.
The Radeon HD 6790 beats the GeForce GTX 550 Ti once again, enjoying an advantage up to 27%. The new card from AMD is also 10% faster than the HD 5770 and 12-20% slower than the HD 6850. AMD’s solutions are overall superior to their Nvidia counterparts in this game.
Here is a table with the test results:
Now let's check out the summary diagrams.
The summary diagrams show the performance of the graphics cards at their default frequencies. The first of them is indicative of the advantage of the new Radeon HD 6790 ($149) over the Radeon HD 5770 ($129) where the latter's speed serves as a baseline. The dotted line marks the difference in their recommended prices which amounts to 15.6%.
So, the Radeon HD 6790 is an average 15% ahead of the Radeon HD 5770 without FSAA and 13% ahead with 4x or 8x MSAA. The new card enjoys the biggest advantage in Unigine Heaven Demo, Left 4 Dead 2 and Tom Clancy’s H.A.W.K. 2. The smallest advantage can be observed in F1 2010 and in the FSAA-less mode of StarCraft II: Wings of Liberty and Mafia 2.
The next diagram shows how slower the Radeon HD 6790 is against the Radeon HD 6850.
Thus, the Radeon HD 6790 is an average 13% and 18% slower in the FSAA-less and FSAA modes, respectively. Although these numbers are somewhat higher than the Radeon HD 6790’s advantage over the Radeon HD 5770, we can see that the new card fits in nicely between the two older products.
Now let’s compare the two direct rivals: AMD Radeon HD 6790 and Nvidia GeForce GTX 550 Ti.
The diagram makes it clear that the Radeon HD 6790 is inferior to the GeForce GTX 550 Ti in but a few tests, namely Far Cry 2, Lost Planet 2, Tom Clancy’s H.A.W.K. 2 and in the high-quality mode of StarCraft II: Wings of Liberty. The two cards are equals in Resident Evil 5 and Borderlands. The rest of the tests are won by the new card from AMD which enjoys an advantage of up to 30%. The Radeon HD 6790 is an average 13.3% ahead of the GeForce GTX 550 Ti across all the tests in the FSAA-less mode and 4.8% ahead in the FSAA mode.
And the final diagram compares the Nvidia GeForce GTX 460 with the AMD Radeon HD 6850. I’ll leave it uncommented.
I measured the power consumption of systems with different graphics cards (the monitor excluded) using a specially modified power supply at two loads. The typical gaming load was emulated by running two cycles of the Aliens vs. Predator benchmark at 1920x1080 with 16x AF and 4x MSAA. To create maximum load I launched FurMark 1.8.2 (in stability check mode at 1920x1080 with 16x AF) singly and together with Linpack x64 (LinX 0.6.4, 4750 MB, 5 threads). These two programs load heavily the graphics card and CPU, respectively, so I can determine the peak power draw of the whole system and see what power supply will suffice for it (taking the PSU’s efficiency into account).
You can see the results in the diagram:
The AMD Radeon HD 6790 system needs about 8% more power than the same system with a Radeon HD 5770 and a mere 2% more than the HD 6850 system. This might be expected since the new card is closer to the HD 6850 and HD 6870 than to AMD's junior series in its design and specs. The Radeon HD 6790 is better than its direct rival, GeForce GTX 550 Ti, which consumes 10% more power. Moreover, the GTX 550 Ti configuration turns out to be the most voracious at the default frequencies, consuming more power than the senior GeForce GTX 460. Overclocking changes the picture, though.
Overall, you can see that even if used together with an overclocked six-core CPU (which is rather unlikely considering the pricing of the tested graphics cards) and other components, these cards will not call for a power supply with a wattage rating of more than 550 watts.
According to my tests, the AMD Radeon HD 6790 is exactly midway between the Radeon HD 5770 and Radeon HD 6850 in performance. The new GPU and the 256-bit memory bus make the new card superior to the HD 5770, by about 15% on average, despite the lower frequencies. On the other hand, the HD 6790 has fewer ROPs and shader processors than the Radeon HD 6850, so the latter is 15-16% faster on average. Thus, the new card fits into the previously unoccupied market niche, completing AMD's entry-level product range. Besides, it proves to be overall faster than its direct rival GeForce GTX 550 Ti. It must be noted, however, that these cards from Nvidia feature higher overclocking potential than the Radeon HD 6790 and may use this advantage to catch up with the latter in some games or tests. On the other hand, we are yet to see off-the-shelf HD 6790s and check out their overclockability.
The reference Radeon HD 6790 consumes less power than the GeForce GTX 550 Ti, which is important for mainstream and low-end graphics cards, but produces more noise and has larger dimensions. So, much depends on AMD's partners and their ability to quickly deliver custom-designed Radeon HD 6790s with smaller PCBs, one power connector and factory overclocking. I have no doubt such products will come out very soon. By the way, a good example of such a custom-made graphics card is the HIS Radeon HD 6850 IceQ X Turbo I've tested today.
We, at X-bit labs, will be keeping an eye on this market sector to report to you about such products as soon as they are released.