Roundup: Radeon HD 7790 Based Graphics Cards

Let’s find out which one is the best of the five: the Radeon HD from Asus, Gigabyte, HIS, MSI or Sapphire. We will also run some tests in CrossFireX mode.

by Sergey Lepilov
08/16/2013 | 03:34 AM

Some time ago we tested seven variants of the GeForce GTX 650 Ti Boost graphics card and promised to write a similar review about its main opponent AMD Radeon HD 7790. We have indeed managed to collect five original versions of the latter card:

 

One of them features 2 gigabytes of onboard memory, so we will be able to check out the practical benefits of the double amount of memory on this entry-level solution. We will also benchmark a CrossFireX tandem built out of two Radeon HD 7790s in comparison with a higher-class single-GPU product that would cost the same money. So, we’ve got quite a lot of information to share with you in this review.

Technical Specifications Overview

The technical specifications of all Radeon HD 7790 based graphics cards discussed today are summed up in the following table side by side with the reference product for comparison purposes:

 

Testing Participants

ASUS HD 7790 DirectCU II 1GB (HD7790-DC2OC-1GD5)

ASUS offers two Radeon HD 7790s differing only in the amount of onboard memory. We’ve got the HD7790-DC2OC-1GD5 model which is equipped with 1 gigabyte of it. The card is shipped in a compact box that’s covered with descriptions of product features:

 

 

Besides the graphics card, the box contains a CrossFireX bridge, a DVI->D-Sub adapter, a CD with drivers and ASUS GPU Tweak utility, and a brief installation guide.

The product is manufactured in China and comes with a 3-year warranty. Its minimum retail price is $150.

The ASUS HD 7790 DirectCU II is rather compact. It is only 216 mm long, and even this length is due to the oversized DirectCU II cooler:

Besides a standard set of video connectors (dual-link DVI-I and DVI-D, HDMI 1.4a and DisplayPort 1.2), there is a vent grid in the card’s mounting bracket to exhaust the hot air out of the computer case.

The card has one MIO connector for building CrossFireX tandems and a 6-pin power connector.

 

Its power draw is specified to be no higher than 85 watts in 3D applications. A 500-watt PSU is recommended for a computer with one Radeon HD 7790 inside.

The ASUS HD 7790 DirectCU II has the reference PCB design with 5-phase power system.

The power system is governed by an ON Semiconductor NCP81022 controller which doesn’t support software-based voltage management.

The GPU lacks a protective frame, so you have to be extremely cautious when removing or installing the cooling system.

The GPU die was manufactured on the 6th week of 2013 in Taiwan. It is pre-overclocked by 75 MHz (+7.5%) compared to the reference Radeon HD 7790, so its clock rate in 3D applications is 1075 MHz. In 2D applications the GPU frequency is lowered to 300 MHz. The ASIC quality of the chip is 66.3%:

The card carries four FCBGA-packaged chips for a total of 1 GB of GDDR5 memory. These are H5GQ2H24AFR R0C chips from Hynix Semiconductor:

Rated for 6000 MHz, the memory chips are clocked at 6400 MHz on the ASUS card. In 2D mode the frequency is lowered to 600 MHz. The memory bus is 128 bits wide, so the peak bandwidth is 102.4 GB/s, which is 6.7% higher than the reference card’s.

The DirectCU II cooler is in direct contact with the GPU whereas the power components lack any heatsink and are only cooled by the air flow from the fans.

The cooler consists of an aluminum heatsink with two 6mm heat pipes and thin aluminum fins. It has a plastic casing with two 75mm fans.

The speed of the fans is PWM-regulated in a range of 1100 to 3500 RPM. Here’s a picture of the direct-touch technology implemented in the ASUS DirectCU II cooler:

Hereinafter, to check out the cards temperatures we used five runs of the pretty resource-hungry Aliens vs. Predator (2010) benchmark at the highest visual quality settings, at a resolution of 2560x1440 pixels. We used 16x anisotropic filtering but no MSAA 4x, because this load would be too much for the video memory on these graphics cards to handle, and the GPU wouldn’t heat up as much as we needed it to.

We used MSI Afterburner 3.0.0 beta 10 and GPU-Z version 0.7.1-0.7.2 for monitoring of temperatures inside the closed system case, which configuration is discussed in detail in the corresponding chapter of the roundup. All tests were performed at 27-28°C room temperature.

When the fans were regulated automatically and reached a speed of 1790 RPM, the GPU was only 64°C hot.


Auto fan mode

Maximum fan speed

At the maximum speed of the fans (3430 RPM), the GPU temperature went down to 57°C, so ASUS’s exclusive DirectCU II cooler proved its high efficiency once again.

As for the overclocking potential of the ASUS HD 7790 DirectCU II, we could increase its GPU clock rate by 145 MHz. The memory chips could only be overclocked by 240 MHz:

Thus, the overclocked card worked at 1220/6640 MHz.

The overclocked ASUS HD 7790 DirectCU II had a GPU temperature of 65°C at 1900 RPM.

 

Gigabyte Radeon HD 7790 OC 2GB (GV-R779OC-2GD)

Gigabyte Technology also offers two Radeon HD 7790 models but we’ve got the 2GB version now. The model name, memory amount and GPU frequency are indicated on the front of the cardboard box.

 

On the back, you can find descriptions of the cooler and key product features. Included into the box are a power adapter, a software CD, and a brief installation guide:

The graphics card is manufactured in China and costs $170. The warranty period is 3 years.

The Gigabyte Radeon HD 7790 OC is the longest card in this review at 267 mm. With its large dimensions and dual-fan cooler, it doesn’t really look like an entry-level product.

The video outputs are perfectly standard: two DVI ports, one HDMI and one DisplayPort.

There are also no differences from the reference card in terms of CrossFireX and power connectors:

 

However, the Gigabyte is the only card in this review for which a 450 rather than 500-watt PSU is recommended. Notwithstanding the larger PCB, the card uses the reference design:

Featuring Gigabyte’s Ultra Durable technology, the card employs low-RDS(on) MOSFETs, Japanese solid-state capacitors and ferrite-core chokes. Its power system is governed by an ON Semiconductor NCP81022 controller you can see on the reverse side of the PCB.

The GPU only differs from the ASUS card’s in its date of manufacture (8th week of 2013).

Like with the ASUS card, the GPU frequency is 1075 MHz in 3D applications. The ASIC quality of the chip is somewhat higher at 73.5%.

The Gigabyte has the same memory chips as the ASUS card. There are 8 of them, located on both sides of the PCB:

The difference is in the total amount. Instead of 1 GB, the Gigabyte Radeon HD 7790 OC has 2 GB of onboard memory. The memory is not pre-overclocked and works at 6000 MHz.

The Gigabyte Radeon HD 7790 OC is equipped with a WindForce series cooler which is called Triangle Cool. It is rather simple in design, consisting of an aluminum heatsink with one direct-touch 6mm heat pipe and a plastic casing with two fans.

The fans are 95 mm in diameter. Their speed varies from 1300 to 2600 RPM by means of changing their voltage. In the automatic regulation mode the speed of the fans was no higher than 1800 RPM and the GPU temperature was only 60°C.


Auto fan mode

Maximum fan speed

That’s an excellent result. You can also set the fans at their maximum speed to lower the temperature to 56°C.

The GPU of the Gigabyte Radeon HD 7790 OC could be overclocked by the same 145 MHz as the GPU of the ASUS card but the memory chips did better and accelerated by 880 MHz.

So the Gigabyte card was stable at 1220/6880 MHz.

The overclocked card was 61°C hot, its fans rotating at 1830 RPM.

Thus, despite the seemingly simple design, Gigabyte’s cooler copes with its job just perfectly.

HIS 7790 iCooler Turbo 1GB (H779FT1GD)

There are four Radeon HD 7790 models in the product range of Hightech Information System Limited. We’ve got the H779FT1GD model with 1 GB of memory and iCooler.

The product box is large and vertical. There’s a picture of a sword, a Turbo sticker, and some key product information on the front of the packaging.

 

AMD’s technologies and system requirements are described on the back of the box. You can also see a list of awards from mass media there. The card is shipped together with a drivers and utilities CD, a DVI->D-Sub adapter, an installation guide, and a computer transportation notice.

The card is manufactured in China and costs $130, which is very inexpensive compared to the two products discussed above. The warranty period is 3 years.

The HIS 7790 iCooler Turbo is exceedingly simple. Its face side is covered by the cooler’s plastic casing with a small fan in the center.

The casing is larger than the PCB by 37 mm, making the card longer. It is a shame as the product might have been even more compact than its current 210 mm.

The HIS version has a standard set of video outputs…

…MIO and power connectors:

 

The PCB follows the reference design with a NCP81022 controller:

Manufactured on the week between the GPUs of the ASUS and Gigabyte cards, this chip lacks a protective frame, too.

Surprisingly, its 3D clock rate is 1075 MHz, too. So, we’ve got three almost identical GPUs so far. Its ASIC quality is somewhat different, though, at 70.1%.

The HIS card has 1 GB of memory in the same Hynix chips as we’ve seen on the ASUS and Gigabyte cards:

The memory is pre-overclocked from 6000 to 6400 MHz in 3D applications, making this card one of the fastest three in this review. The GPU-Z utility shows us the full specs:

The HIS 7790 iCooler Turbo has a primitive cooler: a piece of aluminum with a copper base and a 75mm fan.

There’s a heatsink on the power components, cooled by the same air flow.

The HIS card is considerably cheaper than the above-discussed products from ASUS and Gigabyte, so its cooler is low-end, too. Reaching a fan speed of 1880 RPM in the automatic regulation mode, the cooler kept the temperature at 68°C, which is higher than the GPU temperature of the ASUS or Gigabyte.


Auto fan mode

Maximum fan speed

At the maximum speed of 4190 RPM, the peak temperature was 62°C. Notwithstanding the humble cooler, the GPU could be overclocked somewhat better, by 175 MHz, than on the previous cards.

The memory chips were only stable at 6640 MHz, though:

Working at 1250/6640 MHz, the HIS 7790 iCooler Turbo had a GPU temperature of 70°C and a fan speed of 1920 RPM.

 

MSI Radeon HD 7790 OC 1GB (R7790-1GD5/OC)

MSI offers as many as four Radeon HD 7790s with different clock rates and memory amounts. We’ve got the R7790-1GD5/OC model which features factory overclocking but is only equipped with 1 gigabyte of memory.

Besides the model name and key product features, you can see a picture of some mysterious thing on the front of the box. The thing has the name of the well-known MSI Afterburner utility on it.

 

We’ve got the same entry-level accessories here:

Manufactured in China, the card comes with a 3-year warranty at a retail price of only $130.

The MSI Radeon HD 7790 OC is the smallest card in this review, measuring 188x110x36 mm. Its cooling system is a mere 10 mm larger than the PCB on two sides.

The video outputs are standard but the DVI connectors are blue here.

The MIO and 6-pin power connectors are standard as well, so we won’t show you their photo again.

The MSI card uses the reference PCB design and features high-quality Military Class III components that comply with the American military standard MIL-STD-810G. So we can see here solid-state capacitors with ultra-low resistance and 10-year service life as well as Super Ferrite Chokes with 10% higher energy efficiency and 30% higher current capacity compared to ordinary chokes.

It’s nice that components MSI used to install on hi-end products are now available on entry-level products as well.

MSI has no power to tweak the GPU, though, so we have the same Bonaire chip manufactured on the 7th week of this year. It is without a protective frame again.

It is pre-overclocked to 1050 MHz, which is a lower frequency compared to the three previous products. The ASIC quality of the chip is 70.6%.

There is 1 gigabyte of onboard memory in the same Hynix chips as we can see on the other graphics cards in this test session:

The memory frequency is standard, so the MSI Radeon HD 7790 OC has the same specs as the reference card except for the GPU clock rate:

The MSI has a simple cooler: a small aluminum heatsink pierced by two 6mm heat pipes with direct-touch technology. The whole thing is cooled by a 94mm impeller with curved blades.

 

These special Propeller Blades are supposed to generate 20% higher air flow compared to ordinary impellers. The speed of the fan is PWM-regulated in a range of 1500 to 3000 RPM.

Despite its simplicity, the cooler is quite efficient. With its fan regulated automatically, it kept the GPU temperature below 60°C.


Auto fan mode

Maximum fan speed

At the maximum speed of 2910 RPM, the GPU was 54°C hot. Running a little ahead, we can tell you that it’s the best result in this test session.

The card has high overclocking potential. We managed to speed up its GPU by 190 MHz and its memory by 1120 MHz.

Thus, the MSI has the best overclocking result overall: 1240/7120 MHz.

The overclocked card had a 4°C higher temperature while its fan accelerated by about 100 RPM.

 

Sapphire Radeon HD 7790 DUAL-X OC 1GB

Sapphire Technology has released three Radeon HD 7790 models so far. One of them has 2 GB of memory and the other two, 1 GB. We’ve picked up the faster of the 1GB versions which is called Sapphire Radeon HD 7790 DUAL-X OC.

Sapphire’s packaging seems to be the most aggressive with pictures of a warlike girl with a rifle on both sides of the box.

 

Sapphire offers the best accessories. Besides power cables, adapters, a software CD and documentation, there is an HDMI cable in the box.

A sticker with Sapphire logo is included into the box, too. The card is manufactured in China and costs $130. Its warranty lasts 3 years.

The Sapphire card is cute and small, just like an entry-level product should look, in our opinion. Its face side is covered by a sculpted plastic casing with two fans:

The Sapphire Radeon HD 7790 DUAL-X OC measures 216x101x37 mm (without the mounting bracket). It has a standard selection of video outputs:

Its CrossFireX and power connectors are standard, too:

 

The PCB follows the reference design in terms of component layout and power system configuration. The empty right part of the PCB seems to have been added to match the cooler, which is longer.

Like on every other card in this review, the power system is managed by a NCP81022 controller:

The GPU of the Sapphire card has a protective frame, so there’s lower risk of damaging it while installing or uninstalling the cooler.

The GPU is pre-overclocked to 1075 MHz in 3D applications. It has the highest ASIC quality in this review:

The memory chips are the same as we’ve seen on the other cards:

There’s a total of 1 GB of memory, which is pre-overclocked to 6400 MHz.

Sapphire’s DUAL-X cooler is quite interesting. It consists of an aluminum base with copper core two identical heatsinks are soldered to.

The heatsinks are pierced with 8mm heat pipes that go out of the cooler’s base. The aluminum plate additionally contacts with the memory chips via thermal pads. There’s a small aluminum heatsink on the power transistors.

The whole arrangement is cooled by two 75mm FirstD fans.

Their speed is PWM-regulated in a range of 1100 to 4400 RPM. When regulated automatically, the fans reached the highest speed in this test session – 2860 RPM. However, the DUAL-X isn’t the best cooler in terms of GPU temperature, which was 67°C.


Auto fan mode

Maximum fan speed

At the maximum speed of the fans the temperature was a mere 6°C lower, which is quite a modest result compared to the leaders of this review.

On the other hand, the Sapphire Radeon HD 7790 DUAL-X OC reached the highest GPU frequency during our overclocking experiments. We managed to increase it by 185 MHz.

The memory wasn’t that good, yet reached 6840 MHz.

The overclocked card had a GPU temperature of 70°C and its fans were rotating at 3000 RPM.

It looks like the Sapphire can hardly beat the others in terms of noiselessness, but we’ll check out its noise level in the next section anyway.

Noise Level, Temperature, Power Consumption

The noise level of each cooler was measured between 1:00 and 3:00 AM in a closed room about 20 m2 big using CENTER-321 electronic noise meter. The noise level for each cooler was tested outside the system case when the only noise sources in the lab were the cooler and its fan. The noise meter was installed on a tripod and was always at a 150 mm distance from the cooler fan rotor. The tested cooling systems were placed at the edge of the desk on a sheet of polyurethane foam. The lowest noise reading our noise meter device can register is 29.8 dBA and the subjectively comfortable noise level in these testing conditions was around 36 dBA (do not mix it up with low noise level). The fan(s) rotation speed was adjusted in the entire supported range using our precise in-house controller by changing the voltage with 0.5 V increment.

The vertical dotted lines mark the peak speed of the cooler’s fan(s) in the automatic regulation mode. Here are the results:

The noise level graph of the Sapphire card goes lower than the others, but the dotted lines indicate that the Sapphire and the MSI are the noisiest cards in the automatic fan regulation mode. It is indeed so subjectively. The ASUS HD 7790 DirectCU II is, on the contrary, the quietest card here, followed by the HIS. The Gigabyte with WindForce cooler takes an in-between position. We should note, however, that none of these five graphics card is really quiet in 3D applications.

The following diagram shows the noise level of the cards in the automatic fan regulation mode and at the maximum speed of the fan(s) and also shows the peak GPU temperature. The graphics cards are sorted in the order of ascending GPU temperature:

The MSI has the lowest GPU temperature in both fan regulation modes, but it is not a leader in terms of quietness. It is followed by the Gigabyte and the ASUS, the latter being the leader in terms of noise level. The Sapphire and the HIS have the least efficient coolers, yet they also manage to keep the factory-overclocked GPUs colder than 70°C.

The temperature of the cards doesn’t change much when they are overclocked (in the automatic fan regulation mode):

The Gigabyte is ahead now, replacing the MSI. They are followed by the ASUS whereas the Sapphire and the HIS take last places.

We measured the power consumption of our testbed equipped with different graphics cards using a multifunctional Zalman ZM-MFC3 panel which can report how much power a computer (without the monitor) draws from a wall outlet. There were two test modes: 2D (editing documents in Microsoft Word or web surfing) and 3D. In the latter case the load was created by four runs of the introductory “Swamp” scene in Crysis 3 game at 2560x1440 with maximum image quality settings, but without MSAA.

In our power consumption test we will check out Radeon HD 7790s that have different amounts of memory, a configuration with a CrossFireX tandem built out of two Radeon HD 7790s, and two Nvidia-based cards:

As you can see, the different Radeon HD 7790 variants don't differ much in their power draw, so the amount of onboard memory doesn't affect power consumption much. The two Radeon HD 7790s in CrossFireX mode need 94 watts more, being comparable to the single GeForce GTX 760 in this parameter. The configuration with one GeForce GTX 650 Ti Boost needs 50 watts more at peak load than the configuration with one Radeon HD 7790 2GB.

Testbed Configuration and Testing Methodology

We have already tested Radeon HD 7790 performance in our previous article, therefore today we are going to compare side by side two Radeon HD 7790 based graphics cards working at identical frequencies, but featuring different amount of memory: 1 GB vs. 2 GB. We will also test a pair of identical 1 GB graphics cards in a CrossFireX configuration. It was fairly easy to find a competitor for them, because a pair of 1 GB Radeon HD 7790 based graphics accelerators costs around $260-$280. Today they will be competing against a new Zotac GeForce GTX 760, which we will review in greater detail in our next article. We also added a GeForce GTX 650 Ti BOOST here, for comparison purposes.

All participating graphics cards were tested in a system with the following configuration:

You have already seen all graphics cards on AMD chips earlier in this review, so here are their competitors from the “green” camp:

  

 

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 48x, BCLK frequency set at 100 MHz and “Load-Line Calibration” enabled to 4.8 GHz. The processor Vcore was increased to 1.38 V in the mainboard BIOS:

Hyper-Threading technology was enabled. 32 GB of system DDR3 memory worked at 2.133 GHz frequency with 9-11-11-31 timings and 1.6V voltage.

The test session started on June 8, 2013. All tests were performed in Microsoft Windows 7 Ultimate x64 SP1 with all critical updates as of that date and the following drivers:

We tested the graphics cards performance in two resolutions: 1920x1080 and 2560x1440. The tests were performed in two image quality modes: “Quality+AF16x” – default texturing quality in the drivers with enabled 16x anisotropic filtering and “Quality+ AF16x+MSAA 4x(8x)” with enabled 16x anisotropic filtering and full screen 4x or 8x antialiasing, in those cases when the average fps rate remained high enough for comfortable gaming experience. We enabled anisotropic filtering and full-screen anti-aliasing from the game settings. If the corresponding options were missing, we changed these settings in the Control Panels of Catalyst and GeForce drivers. We also disabled Vsync there. There were no other changes in the driver settings.

The benchmarking suite used this time included two popular semi-synthetic benchmarks and 11 resource-consuming games of various genres:

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.

Performance

3DMark 2013

We’ve got interesting results in 3DMark 2013: the amount of onboard memory doesn’t affect the performance of the Radeon HD 7790 in the Cloud Gate and Fire Strike scenes, but the 2GB version is as much as 70% faster in the heaviest test Fire Strike Extreme. That’s impressive, even though the scores are very low. We wonder if we’ll see the same in actual games. The CrossFireX tandem built out of two Radeon HD 7790s is faster than the single factory-overclocked GeForce GTX 760 in the first two scenes but falls behind the latter in Fire Strike Extreme. That must be due to the 128-bit bus and the small amount of graphics memory of the Radeon HD 7790.

Unigine Valley Bench

We see the same picture in this test:

The GeForce GTX 650 Ti Boost enjoys a large advantage over the Radeon HD 7790 with the same amount of memory, although these graphics cards cost the same money!

Total War: SHOGUN 2 – Fall of the Samurai

There’s almost no difference between the 1GB and 2GB versions of the Radeon HD 7790 in the first game on our list – a mere 2 fps at the AA settings. The CrossFireX tandem is 90% faster than the single HD 7790 and beats the GeForce GTX 760 when antialiasing is turned off. The latter is 1 fps ahead with 4x MSAA. The GeForce GTX 650 Ti Boost 2GB is again faster than the Radeon HD 7790 2GB.

Battlefield 3

Battlefield 3 doesn’t show any benefits from having 2 GB of memory on a Radeon HD 7790, either. The Radeon HD 7790 CrossFireX configuration beats the single GeForce GTX 760 in both test modes, even in terms of the bottom speed.

Sniper Elite V2 Benchmark

The CrossFireX tandem fails in this game:

The bottom frame rate of the CrossFireX configuration is too low, although it’s important for smooth gameplay. Judging by the performance of the single Radeon HD 7790 and the higher results of the 2GB version, the problem is caused by the lack of graphics memory. We've noted this fact with top-end products, so entry-level cards are going to suffer from it even more. At the same time, the average frame rate is quite high on the CrossFireX tandem – almost 100% higher in comparison with the single card. But again, the low bottom speed spoils all the fun.

Sleeping Dogs

The CrossFireX tandem looks much better here, even beating the GeForce GTX 760. The 1GB and 2GB Radeon HD 7790s deliver the same performance.

Hitman: Absolution

The 1GB Radeon HD 7790 has problems with bottom speed in this game, both as a single card and as a CrossFireX tandem.

Crysis 3

1 GB of graphics memory seems to be a limiting factor in Crysis 3, even though not as much as in Sniper Elite V2 or Hitman: Absolution.

At the same time, the Radeon HD 7790 CrossFireX tandem is quite competitive against the new GeForce GTX 760 in terms of average frame rate.

Tomb Raider (2013)

The CrossFireX technology is highly efficient in Tomb Raider, so the two 1GB Radeon HD 7790s are twice as fast as the single such card. There are no problems with the bottom speed here.

BioShock Infinite

BioShock Infinite suggests that building an entry-level CrossFireX tandem isn’t a good idea: the average frame rate grows up but the bottom speed goes down.

Metro: Last Light

The CrossFireX tandem is somewhat better in this game:

There are no problems with the bottom speed whereas the average frame rate grows up just as expected.

GRID 2

The two Radeon HD 7790s are good in GRID 2, probably due to the overall optimization of the game engine for AMD GPUs.

Company of Heroes 2

Even with latest game patches and newest drivers, the CrossFireX technology just doesn’t work in Company of Heroes 2.

So, this is the only game in our review where AMD’s multi-GPU technology fails to work at all. Also in this game we can see the largest difference between the 1GB and 2GB Radeon HD 7790s.

Performance Summary Diagrams

Here is a table with full test results, so we can proceed to our summary charts.

First of all, we want to see the difference between Radeon HD 7790s with 1 and 2 gigabytes of onboard memory, the 1GB version serving as a baseline:

The Radeon HD 7790 can really benefit from an extra gigabyte of memory. The 2GB version is almost twice as fast in Company of Heroes, 15% faster in Tomb Raider and 7% faster in Total War: Shogun 2 - Fall of the Samurai and Crysis 3. The Fire Strike Extreme scene from 3DMark (2013) may also be mentioned. Still, we don’t think that this inconsistent performance boost is worth the $40 difference in price we see between the two versions. Moreover, in those cases where we see the difference in speed, the frame rate is anyway too low for comfortable play.

The next diagram shows the efficiency of the CrossFireX technology as applied to two 1GB Radeon HD 7790s in terms of average frame rate.

The CrossFireX tandem is much faster in every game, save for Company of Heroes 2: by an average 80% without antialiasing and by an average 82% with antialiasing. Unfortunately, the bottom speed doesn’t grow up proportionally.

The last diagram helps us compare the Radeon HD 7790 CrossFireX configuration with a single factory-overclocked GeForce GTX 760.

The two Radeon HD 7790s are often faster than the single GeForce GTX 760 and even much faster in two games (GRID 2 and Tomb Raider without SSAA). In its turn, the GeForce GTX 760 is superior in Company of Heroes 2 because the CrossFireX technology failed to work in that game. Anyway, considering that both solutions cost the same money, we'd prefer the single GeForce GTX 760 which has no problems with bottom speed which plague the entry-level CrossFireX tandem.

Conclusion

We’ve tested five Radeon HD 7790 models today and find it hard to name an overall winner among them. The ASUS version is the quietest. The MSI has the most efficient cooler, overclocks well and is compact. The Gigabyte has 2 GB of graphics memory, even though their benefits are not so obvious. The Sapphire has the best accessories and packaging. The HIS version seems to be ordinary compared to the others, but it costs as much as a reference Radeon HD 7790 while being pre-overclocked to 1075/6400 MHz. Their GPUs are similar in terms of ASIC quality and don't differ much in overclocking potential (±20 MHz). As for memory overclocking, the MSI reached the best result (7120 MHz) while the ASUS and HIS had the worst result (6640 MHz). So, it’s really hard to say which one is better overall.

As for AMD’s multi-GPU technology, we don’t think it has any perspectives for entry-level graphics cards. And even if you really want to build a CrossFireX tandem out of two Radeon HD 7790s, you should take the 2GB version of the card. It may help you avoid problems with bottom speed. As for average frame rate, the efficiency of CrossFireX is quite high, so the multi-GPU technology proves its viability once again.