In the ongoing war of AMD and Nvidia graphics cards, the products of the two companies, as a rule, are clearly divided into clear winners and those that show conflicting results. If the former are leaders in performance and functionality in their price range, the latter are not so clear - they will be the best choice for some users, but the worst for others.
III level map
The second level includes graphics processors that, due to defects, have not passed strict selection. And crystals with the most damaged functional blocks that do not work at lower voltages fall into the third. This does not mean that cards with such cores cannot be good - the HD 4830 and GTX 260 received good reviews, but their result is difficult to repeat.
Although AMD Radeon HD 6790 provides excellent functionality in its price range (about 9,200 rubles), it definitely applies to products of the ІІІ level. This is not only due to performance, because the card works much better than its predecessor HD 5770. But oddly enough, the HD 6790 is larger (1.7 billion transistors versus 956 million) and consumes significantly more power than the higher-end model HD 6850. as well as the relatively inexpensive GeForce GTX 550Tі.
At the time of release, the HD 6790 was the cheapest card in the AMD 6000 series that supports DirectX 11, but with one crucial caveat: if its power requires updating the power supply, then for the majority the best choice would be the HD 6850, which cost in early April 2011 only $ 25 more expensive, but at the same time it provided better performance, greater energy efficiency and compactness.
Architecture
The HD 6790, like the rest of the Barts line, is the direct descendant of the 5800 series cards, in this case the HD 5830. As one would expect, it was further cut back than the 6850, having lost 2 SIMD blocks and half of its ROPs. A small compensation for this was the higher core and memory frequencies. With 800 SP and 16 ROP operating at 840 MHz, the HD 6790 is very similar to the HD 5770 with a 256-bit bus, albeit with a lower frequency of 1050 MHz.
After the video card HD 5830, it became clear that the loss of ROP is much more painful than the loss of SP. Total pixel processing power was halved, and MSAA performance also dropped. Overall, HD 6790 left 90% of the texture units, 54% ROP, half the L2 cache, and 105% of the memory bandwidth of the 6850 card. And compared to the HD 5770, its memory bandwidth increased by 75%, not taking into account the architectural differences between Barts and Juniper .
Design features
For those who used previous AMD 6000 series cards (in particular, HD 6870), the characteristics of the Radeon HD 6790 will seem very familiar. It supports 1 GB of DDR5 memory, has a clock frequency of 840 MHz, and, according to the manufacturer, at full load it consumes about 150 watts. This number is surprising, since the competing GeForce 550Ti video card even in the overclocked Zotac model at maximum load requires only 116 watts. In addition, the more expensive HD 6850 processor consumes a maximum of 127 watts. The Sapphire Radeon HD 6790 is equipped with two 6-pin power connectors, although the HD 6850 and GTX 550Ti have only one.
Just upgrading to the much more expensive AMD HD 6870 card can face similar power requirements. At full load, the HD 6790 consumes 151 watts. This is only 1 W more than the HD 6790. And the similarities do not end there. Implementations of Radeon HD 6850 and 6790, depending on the manufacturer, have sizes of 198–260 mm. Zotac GeForce GTX 550Ti, meanwhile, is a bit shorter - about 190 mm.
All this makes us suspect that, from the point of view of architecture, the HD 6790 is closely connected with the 6870. As with the HD 5830, released back in 2009, this model may be built on higher-end versions (supposedly HD 6870 of a similar size) which did not fully meet the expected specifications and therefore were reconfigured to work in a simpler map.
According to AMD, the design of the model is very different from the typical ones, including a printed circuit board, power connectors, a cooling system, etc. However, third-party manufacturers may offer 1 or 2 power connectors. Therefore, before buying, be sure to carefully read the characteristics of the Radeon HD 6790 specific implementation, since this card has a wider variety of options compared to most other models. The choice of ports can also vary significantly. For example, HIS and XFX manufacturers offer a version with two mini-DisplayPort sockets, an HDMI port (1.4a that supports 3D HDTV) and two DVI ports. It should be noted that the number of ports often varies from seller to seller, so before buying you should make sure that the selected option is equipped with everything necessary.
Like all 2011 AMD products, the Radeon HD 6790 supports DirectX 11, a Microsoft application programming language that improves visual effects. And to use all ports, it implements Eyefinity technology, which provides the ability to connect multiple screens (both to increase productivity and games) and implements support for stereoscopic 3D games. However, given the level of performance, users recommend choosing a more powerful model for the last two options. According to user reviews, multiple screens and 3D tend to have a huge impact on the performance of game cards. However, if you connect more than two monitors, remember that competing Nvidia models only support 2 displays.
Performance testing
When conducting formal testing of the card using the standard 3DMark Vantage synthetic test designed to measure the overall gaming performance of a PC, the Radeon HD 6790 2 GB is slightly behind the GTX 550Tі with a significant lead over the HD 5770. However, after switching to 3DMark 11, which takes into account the use of DirectX 11, The HD 6790 is ahead of 550Ti, although the more expensive 6850 still holds a leading position.
In another DirectX 11-oriented test, Heaven, the GTX 550Ti is leading again.
According to user reviews, a check in the game Aliens vs. Predator demonstrates the superiority of the HD 6790 over the competing card in all resolutions, but the HD 6850 is again significantly ahead of them. The next test, Just Cause 2, is one of the most demanding games with DirectX 10. Here the card surpasses the GTX 550Tі for the first time. Oddly enough, the HD 6790 outperforms the even more expensive HD 6850. The mismatch may be partly related to updating drivers for the video card, since the HD 6850 was tested in October 2010.
Finally, in the oldest and least demanding game Far Cry 2, which debuted in October 2008, the GTX 550Ti shows a significant margin of 5-15 fps.
What do the test results say?
As already mentioned, the characteristics of the Radeon HD 6790 compared to its main competitor, the GeForce GTX 550Tі, are rather ambiguous. It is important to note that many tests give the HD 6790 a slight advantage, and the card is much faster than its predecessor HD 5770. But considering that the HD 6790 consumes more power, even more than the higher-end model HD 6850, the results of the HD 6790 cannot be called a victory.
Overclocking
Radeon HD 6790, according to user reviews, accelerates well, although there is apparently no way to unlock the supply voltage. In this case, you can achieve a maximum frequency of 985 MHz on the core and 1215 MHz in RAM. This is equivalent to 17% and 15% growth, respectively. As users suggest, a BIOS flashing could probably unlock hidden specifications such as additional stream processors. If possible, it will certainly provide the card with additional value.
Power
According to user reviews, they do not understand what voltage in the card is accepted by default. None of their usual tools could recognize the 6790. Probably, AMD used other controllers than the 6800 series, or, perhaps, this is due to the drivers for the video card. In any case, it is close to a voltage of 6870, equal to 1.17 V.
Standby power consumption rarely varies in GPUs of different classes, so the fact that the 6790 consumes as much energy as the 6800 series (161 W) should not be surprising. As a result, the card turned out to be worse than the GTX 550Tі, but almost the same as the GTX 460.
Given the calculated power figures, one would expect that the test results would be much worse than the HD 6870. However, this did not happen: the power consumption in Crysis is higher than that of the 6850, but slightly, and amounts to 258 watts. The card's power is less than the GTX 550Ti, although in this game it significantly exceeds the last, and even compared to 5770 it is slightly larger. Of course, higher power consumption at lower performance than the HD 6850 is bad, but could be even worse.
The situation with Furmark is also pleasantly surprising. According to reviews, the Radeon HD 6790 consumes less power than the HD 6850 - 265 watts versus 274 watts. This proves the optimization of the Barts architecture compared to Cypress. And it makes the card more attractive than the GTX 550Tі and GTX 460, since it consumes 40-45 watts less.
Temperature
If the card power in idle mode is identical to the 6800 series and the same cooler is used, then its heating temperature is similar: +71 ° C.
Considering the power consumption, the HD 6870 cooler is redundant for the HD 6790. As a result, the Crysis temperature is quite low, although the cooling system cannot compare with the GTX 460 open cooler.
The heating temperature in the Furmark test is closely correlated with Crysis and is +77 ° C. Using an open cooler could lower it by a few degrees.
Noise level
In idle mode, the noise, as you would expect, is identical to the 6800 series and is 41.5 dB (A).
Under load, it grows in the same way as in 6870, reaching 55.5 dB (A). This is due to the fact that AMD most likely did not optimize the cooler. Given the power data, the 6790 should not be much louder than the 6850.
Finally
Whatever the real reason for the similarity in some characteristics of the Radeon HD 6790 with its more expensive cousin HD 6870, experts do not recommend this card. It is larger and consumes more power than the competing Nvidia and even the HD 6850. And the GTX 550Tі offers similar performance in a more compact package and with less power requirements.
And vice versa, for those who want to improve performance a little and be able to connect multiple screens to one card for games or increase productivity, the best option would be the HD 6850. It is smaller and more efficient. This does not mean that the HD 6790 is a bad card. In many tests, it demonstrated a new level of performance in its price range and will suit the vast majority of gamers who do not want to spend a lot on gaming equipment, but still want to play Portal 2 or Deus Ex with moderate resolution and enabled visual effects. But given all the alternatives, including the GTX 460, the size and power requirements of the HD 6790 mean that many can find better solutions.