by Alexey Stepin , Yaroslav Lyssenko
03/21/2011 | 09:04 PM
New products may occasionally turn out to be no better than older ones as is the case with the VLIW4 and VLIW5 graphics architectures developed by AMD. The Radeon HD 6870 graphics card with its outdated architecture is actually quite competitive to the new Radeon HD 6950 if clocked at a GPU frequency of about 1 GHz. We can only imagine what a VLIW5 graphics core with more subunits and with third-generation tessellators would be capable of but the fact is that AMD’s top-end solutions are now represented by the Cayman architecture with VLIW4 design. At the current moment, we’ve got the following situation in the performance-mainstream sector:
Again, it is yet too early to dismiss the Radeon HD 6870 which has the lowest price among the three graphics cards indicated above. As we found out in our tests of an ASUS HD 6870 DirectCU, this card can challenge a GeForce GTX 560 Ti if overclocked. Of course, the ASUS version is special and cannot be found for the recommended $219; and if priced at about $300, it can't compete with the GeForce GTX 560 Ti, yet ASUS is not the only brand on the market. There are a lot of Barts-based products available at far more affordable prices. The question is how well do they overclock?
Graphics card manufacturers make the choice even harder by offering a lot of various Radeon HD 6870 versions that often have nothing in common except for the AMD Barts processor itself. Some companies focus on overclocking capabilities and unique exterior design while others emphasize the simplicity and low price of their products. Rich accessories or a quiet cooler can also be important marketing factors.
So today we’ve got two Radeon HD 6870 cards from PowerColor and MSI. They are called HD6870 PCS+ and R6870 Hawk, respectively.
We want to pit them against each other to see if their exclusive technologies can help them at overclocking and if they can beat the ASUS HD 6870 DirectCU we tested earlier. Perhaps one of them will turn out to be the best option as a graphics card to buy and overclock. Let's take a look at them first.
This graphics card comes in a large and almost square box which is painted calm blue colors.
The picture on the box shows an F-117 aircraft which is indeed codenamed Nighthawk. The only problem with this allusion is that the F-117, using stealth technology, has rather poor aerodynamic properties and cannot even stay airborne unless helped by advanced flight computers.
The fragile contents of the box are protected well. The graphics card is fixed in a foam-rubber tray below which there is a compartment with accessories. Here they are:
The accessories are good but we didn't find among them a flexible CrossFire bridge which is mentioned on the product page at the MSI website. There is also no mini-DisplayPort -> DVI adapter in the box but you can see V-Check adapters that can be plugged to the appropriate connectors on the card to measure its voltages.
We won’t be talking about similarities to AMD's reference card here because the MSI R6870 Hawk is absolutely unique.
The massive cooler is fastened to the card with only four spring-loaded screws. The rest of the screws hold the plate that cools memory chips and power system components.
That plate can be removed as well, so we can have a closer look at the design of the MSI R6870 Hawk.
The first thing to catch our eye is the tremendous power circuit which includes as many as eight phases whereas the power circuit of the more advanced GeForce GTX 580 has only six! The voltage regulators use high-quality Super Ferrite Chokes and tantalum capacitors (Hi-C CAP).
The GPU voltage regulator is based on a uPI Semiconductor uP6218 controller whereas an uPI Semiconductor uP6122 manages the memory voltage regulator. Oddly enough, the card has only 6-pin PCIe 1.0 power connectors although MSI claims that this power system can yield up to 80 amperes more than the reference card’s.
There are three connectors labeled V-PLL, V-MEM and V-CPU in the top part of the card. They are referred to as V-Check Points and allow you to easily measure the card's voltages. As mentioned above, special adapters are included into the box for you to connect your measuring instruments.
Another interesting feature is the SW-DIP2 switch that selects the operation mode of the card's fans: Performance or Silent. We carried out all our tests in the silent mode. MSI should be given credit for offering the user such broad options in terms of controlling and managing the R6870 Hawk.
There are eight GDDR5 chips from Hynix Semiconductor (H5GQ1H24AFR), each with a capacity of 1 gigabit (32 Mb x 32), on the PCB. They make up a total of 1 gigabyte of onboard graphics memory. Their T2C suffix indicates a rated frequency of 1250 (5000) MHz but the card’s memory frequency is only 1050 (4200) MHz in 3D applications, in full compliance with AMD’s official specs.
The Barts chip of our MSI R6870 Hawk was manufactured on the 45th week of 2010. It has a standard configuration with 1120 ALUs (224 VLIW5 cores), 56 texture-mapping units and 32 raster back-ends. The card is pre-overclocked by 30 MHz, so its GPU frequency is 930 MHz in 3D applications as opposed to the reference Radeon HD 6870’s 900 MHz. The manufacturer didn’t push this card to the limit, obviously leaving that to the enthusiasts this product is targeted at.
As for connectivity options, like the standard Radeon HD 6870, MSI’s version has five connectors in its mounting bracket: two DVI-I and two mini-DisplayPort connectors and one HDMI. This should be enough for any configurations of displays, especially as you can use all the five interfaces simultaneously and even connect a sixth monitor via a DisplayPort switch. You can also buy two R6870 Hawks and unite them into a dual-GPU CrossFireX subsystem.
The cooling system of the R6870 Hawk is high quality like the rest of this device. It is called Twin Frozr III and represents a time-tested design: a large heatsink, a nickel-plated base, five heat pipes and two 80mm fans.
The fans have peculiarly shaped impeller blades which, according to MSI, improve the air flow by 20%. We can’t check out this claim but we can test the cooler’s performance and noisiness. You will see the results shortly. Right now let's take a look at the second card.
The box with the PowerColor card is compact and upright. This shape may make it easier to carry for some people. It is designed like this:
As you can see, the box design is quite conventional and not very informative. The clock rates of the graphics card are not indicated on the box but you can learn the amount and type of its graphics memory there.
The interior of the box is simple, too. The cardboard tray is not much of protection. Besides the graphics card in an antistatic pack, the box contains the following accessories:
The accessories are scanty. We expected to see at least a passive DisplayPort->DVI-D adapter but none can be found inside. On the other hand, the card is equipped with two native DVI connectors. Considering that PowerColor positions it as an affordable product, the scanty accessories can be explained by the manufacturer’s desire to keep the product price low.
The card has a red PCB, which is the color traditionally associated with ATI Technologies and AMD. It is eye-catching and easily recognizable as the result:
As usual, the most interesting things are hidden below the cooling system. It is easy to remove the latter. We only had to unfasten the four spring-loaded screws on the reverse side of the PCB.
Curiously, the PCB design copies the reference one developed by AMD except that a red solder mask is used instead of a dark-gray one. So, there is no point in our describing its details to you because we already did that in our ATI Radeon HD 6800: Generation Next review.
Like on the reference card from AMD, the 4+2 power circuit is based on CHiL Semiconductor CHL8214 and uPI Semiconductor uP6122 controllers. There are two 6-pin PCIe 1.0 power connectors.
The PowerColor HD6870 PCS+ is equipped with GDDR5 chips from Hynix Semiconductor (H5GQ1H24AFR). Each chip is 1 gigabit (32 Mb x 32) in capacity and the suffix T2C denotes a rated frequency of 1250 (5000) MHz. The card's actual memory frequency is 1100 (4400) MHz which is but slightly above the reference card's 1050 (4200) MHz. We can’t expect this to ensure a significant increase in graphics memory bandwidth.
The GPU chip was manufactured on the 43rd week of the last year. Being a regular Barts, it contains 1120 ALUs grouped into 224 stream processors with VLIW5 architecture. It also features 56 texture-mapping units and 32 raster back-ends. The factory overclocking of this card is somewhat more aggressive than that of the ASUS HD 6870 DirectCU. The GPU clock rate is 940 MHz in 3D mode as opposed to the reference card’s 900 MHz. This can be expected to add noticeably to the card’s performance in real-life applications.
PowerColor preferring the reference PCB design, the HD6870 PCS+ also has a standard configuration of interface connectors. You can see two DVI-I ports, one HDMI and two mini-DisplayPorts on its mounting bracket. You can use all five simultaneously or even take a DP 1.2 switch and connect as many as six displays, if you’ve got that many. There is also a CrossFire connector on the PCB for building multi-GPU configurations out of two such cards.
The cooling system of the HD6870 PCS+ looks highly promising at first sight. It features a large 92mm fan and a massive heatsink with three heat pipes.
The pipes are connected to the copper base. Judging by the thermal grease imprint, the spring-loaded screws ensure high pressure, so the performance of the cooler will depend on how efficiently the pipes can transfer heat between the GPU and heatsink. Additionally, the cooling system includes a small heatsink on the power packs of the GPU voltage regulator. It gets some air flow from the cooler’s fan. Let’s see now how this cooler performs in comparison with the cooling system deployed on the MSI R6870 Hawk.
We studied the power consumption of Barts-based solutions in our ASUS HD 6870 DirectCU review. Nonstandard variations of this graphics card can be much more voracious than the reference sample, especially if the user makes some changes to GPU voltage. An overclocked Radeon HD 6870 may need up to 150-160 watts in heavy 3D applications which is roughly equivalent to the power consumption of a non-overclocked GeForce GTX 560. As we found out earlier, these solutions are also comparable in terms performance at such settings.
Now, both graphics cards we are discussing in this review have nonstandard coolers with massive heatsinks and high-performance fans. The MSI card has even two fans, but do they give it any advantage in terms of cooling?
Well, the MSI R6870 Hawk is indeed better than the PowerColor HD6870 PCS+ in 3D applications by as much as 14°C. The ambient temperature being 24-25°C during this test, the card's 62°C under load is an excellent result. Its 32°C in idle mode also seems to be a record-breaking result. On the other hand, the PowerColor cools its GPU quite effectively, too. Its cooler is more efficient than AMD's reference one, especially considering that the PowerColor card is pre-overclocked.
Now let’s check out how much noise the two graphics cards produce, the level of background noise being 38 dBA during this test:
The PowerColor HD6870 PCS+ fails here completely. We don’t know if this is the behavior of our specific sample of the card or the developer deliberately achieved the high cooling performance at the expense of acoustic comfort, but the fan management system is set up very aggressively and quickly accelerates to 73% of the fan’s full speed in 3D mode, making the card very noisy. It is also noisy in idle mode although the fan speed lowers to 21%. Judging by the spectrum of the noise, the fan is not defective. It is just naturally noisy when spinning at high speeds. We hope the fans of off-the-shelf samples of the HD6870 PCS+ will be set up less aggressively.
The MSI R6870 Hawk performs much better here. The large heatsink and the couple of fans do their job well and quietly. The level of noise remains within comfortable limits even at heavy loads when you use the Silent mode although the card is somewhat noisier than the ASUS HD 6870 DirectCU we reviewed earlier. The fan speed rises from 40 to 56% of the maximum then. When not running heavy 3D applications, the Hawk was completely inaudible among the rest of the system components. Thus, you don't really need to switch the fans into the Performance mode.
MSI wins in terms of cooling, but what about overclocking?
We had expected the MSI card to be better in this respect, too. Indeed, the PowerColor HD6870 PCS+ could not even notch 1000 MHz in terms of GPU clock rate despite our increasing its GPU voltage. The MSI R6870 Hawk, on its part, could get as high as 1065 MHz at a GPU voltage of 1.25 volts.
The MSI is also better in terms of memory overclocking yet we are going benchmark both cards at the highest frequencies they achieved.
We are going to test the gaming performance of these two new Radeon HD 6870 models using the following universal testbed:
We used the following ATI Catalyst and Nvidia GeForce drivers:
The ATI Catalyst and Nvidia GeForce graphics card drivers were configured in the following way:
Below is the list of games and test applications we used during this test session:
First-Person 3D Shooters
Third-Person 3D Shooters
Semi-synthetic and synthetic benchmarks
We selected the highest possible level of detail in each game. If the application supported tessellation, we enabled it for the test session.
For settings adjustment, we used standard tools provided by the game itself from the gaming menu. The games configuration files weren’t modified in any way, because the ordinary user doesn’t have to know how to do it. We ran our tests in the following resolutions: 1600x900, 1920x1080 and 2560x1600. Unless stated otherwise, everywhere, where it was possible we added MSAA 4x antialiasing to the standard anisotropic filtering 16x. We enabled antialiasing from the game’s menu. If this was not possible, we forced them using the appropriate driver settings of ATI Catalyst and Nvidia GeForce drivers.
Besides PowerColor HD6870 PCS+ and MSI R6870 Hawk, we also tested the following solutions:
Performance was measured with the games’ own tools and the original demos were recorded if possible. We measured not only the average speed, but also the minimum speed of the cards where possible. Otherwise, the performance was measured manually with Fraps utility version 3.3.2. In the latter case we ran the test three times and took the average of the three for the performance charts.
Well, we already saw this all in our tests of the ASUS HD 6870 DirectCU. Clearly, Barts-based graphics cards need a GPU clock rate of 1 GHz or higher to match the GeForce GTX 560 Ti. Factory overclocking to GPU frequencies of 900-940 MHz is usually not enough for that. It's also clear that you need to overclock such cards in order to make this game playable at 2560x1600.
The MSI R6870 Hawk is expectedly in the lead when overclocked, but when the graphics cards from MSI and PowerColor work in their default mode, they deliver the same performance as they have almost the same GPU and memory clock rates. Overclocking is not rewarding at 2560x1600, by the way, as it ensures but a small performance increase which can hardly be worth the risk of putting the graphics card under stress conditions.
This game having modest system requirements, the Radeon HD 6870 does not really call for additional or even factory overclocking. Every graphics card copes with the game successfully at 2560x1600. The standings are determined by the frequencies achieved in overclocking.
There is no point in overclocking a Radeon HD 6870 for Crysis because you cannot achieve a playable speed in the popular Full HD mode unless you resort to extreme methods like volt modding or cryogen cooling which can hardly be used as long-term measures.
This game is tested with the tessellation option turned on.
Our overclocked MSI R6870 Hawk takes first place, beating the GeForce GTX 560 Ti. Interestingly, the PowerColor is a little bit faster than the Hawk in the default mode, which is due to its more aggressive factory overclocking.
This game runs with enabled tessellation.
At 2560x1600 the performance of a Radeon HD 6870 is not affected much by overclocking in this game whereas at the lower resolutions the frame rate is high without our increasing the clock rates. The MSI R6870 Hawk and the PowerColor HD6870 PCS+ churn out no less than 28-30 fps, achieving an average 40-42 fps, which is quite enough for comfortable play.
It’s like in the previous test. The overclocked MSI R6870 Hawk wins at two out of the three resolutions but overclocking is hardly rewarding here. The game is playable at 1920x1080 without any tweaking but can't be played comfortably at 2560x1600 even if you overclock your MSI R6870 Hawk.
Overclocking is the only means to make this game playable on a Radeon HD 6870, at least at 1600x900. Even the Radeon HD 6950 fails to deliver a playable speed at 1920x1080 whereas the GeForce GTX 560 Ti does that easily. Alas, this game is not favorable to the AMD Barts architecture.
This game is not suitable for benchmarking top-end graphics cards as we can only see any differences between them at a resolution of 2560x1600. Here, the overclocked MSI R6870 Hawk overtakes the Radeon HD 6950 but no gamer can feel the difference in practice.
We enforced full-screen antialiasing using the method described in our special Mass Effect 2 review.
The overclocked MSI R6870 Hawk is the overall winner here although it falls behind the GeForce GTX 560 Ti at 1600x900. It beats every other card, including the Radeon HD 6950, at 1920x1080. The game is playable at 2560x1600 where our overclocking provides a nice addition to the MSI card's bottom speed.
A small difference between the bottom and average frame rates is a characteristic feature of this game which makes overclocking such cards as Radeon HD 6870 unrewarding, even though they can be with some luck overclocked to the level of the Radeon HD 6950 or even made faster than the GeForce GTX 560 Ti at 1920x1080 and higher resolutions.
As we proved in a previous review and as is indicated by the results of the gaming tests above, an overclocked Radeon HD 6870 can challenge the newer Radeon HD 6950 in some situations. It finds it harder to compete with Nvidia’s solutions, though, especially in games like BattleForge. The GeForce series always has a higher bottom speed here as opposed to AMD's products which cannot keep the frame rate above 15-18 fps.
The Radeon HD 6870s run this game quite fast, especially when overclocked, at resolutions up to 1920x1080 but cannot achieve a playable frame rate in the Ultra HD mode. The GeForce GTX 560 Ti can’t do that either, though.
We minimize the CPU’s influence by using the Extreme profile (1920x1200, 4x FSAA and anisotropic filtering). We also publish the results of the individual tests across all resolutions.
The overclocked MSI R6870 Hawk scores over 10,000 points, improving on the result of the ASUS HD 6870 DirectCU. That’s an excellent performance for a Barts-based solution which is thus placed higher than the GeForce GTX 560 Ti but somewhat below the Radeon HD 6950.
Like with the ASUS HD 6870 DirectCU, the performance benefits from overclocking the MSI R6870 Hawk amount to 9 to 17% depending on the particular test and resolution. The overclocked PowerColor HD6870 PCS+ is 7 to 10% ahead of the reference AMD Radeon HD 6870.
We use the Extreme profile here. As opposed to 3DMark Vantage, this profile uses a resolution of 1920x1080 pixels.
The MSI R6870 Hawk can’t notch 1500 points here, leaving that to the Radeon HD 6950. The performance increase of the overclocked cards from MSI and PowerColor over the reference Radeon HD 6870 is 12% and 10%, respectively.
This benchmark can only run at 1280x720 and 1920x1080.
The Radeon HD 6950 is hopelessly behind the Radeon HD 6870 at 1280x720 despite the latter card’s older architecture. This must be due to the Radeon HD 6950’s VLIW4 design of stream processors which do not have a dedicated ALU for complex instructions and have to perform such instructions by using four simpler ALUs. Things are better for the newer card at 1920x1080 yet the overclocked Radeon HD 6870 beats it anyway.
This benchmark makes wide use of tessellation to render the surface of the earth. The number of polygons per one frame can be as high as 1.5 million!
Ironically, the MSI Hawk doesn’t soar very high on its Barts engine in its namesake game. The newer fighters, AMD Cayman and Nvidia Fermi, are superior in this test, but the Radeon HD 6870 can deliver high performance even at 2560x1600.
We use Normal tessellation in this test.
The overall picture is similar to what we’ve seen in H.A.W.X. 2 but the frame rates are much lower. AMD’s second-generation tessellation unit can’t cope with this test. It is only through overclocking that we can increase the bottom speed of the MSI R6870 Hawk to the level of the GeForce GTX 560 Ti at the lowest resolution.
We have not learned anything particularly new from the fight between the MSI R6870 Hawk and the PowerColor HD6870 PCS+ as we saw the same results in our review of the ASUS HD 6870 DirectCU. We can again say that AMD’s old graphics architecture with VLIW5 execution units is not really outdated. If clocked at high frequencies, it can compete with the new VLIW4 architecture and even beat it by utilizing a dedicated ALU for carrying out complex instructions.
In fact, the single bottleneck of the Barts core is a relatively weak second-generation tessellation unit whereas the new Cayman features third-generation tessellators. This is especially conspicuous in Unigine Heaven. Yet the results of the other tests suggest that the Radeon HD 6870 is competitive to the GeForce GTX 560 Ti as well as to the Radeon HD 6950 if clocked at a GPU frequency of 1 GHz and higher.
The problem is that overclocking is lottery. You can be lucky like we were with the MSI R6870 Hawk but there is also a chance of damaging your card by increasing its GPU voltage too high. You can also get a sample with low overclocking potential like our PowerColor HD6870 PCS+ whose GPU could not be sped up even to 1 GHz. You should also keep it in mind that your choice between a Radeon HD 6870 for overclocking and a GeForce GTX 560 Ti for using at its default clock rates should be based on your favorite games and their preferences regarding the competing graphics architectures.
Comparing the two specific Radeon HD 6870 models discussed in this review, our favorite is the MSI R6870 Hawk. It is a high-quality product with high overclocking potential and a number of overclocker-friendly features. It also has a high-performance and quiet cooler. The single downside is its rather high price. This original Radeon HD 6870 can be found selling for about $235. A GeForce GTX 560 Ti is a mere $10 more expensive and also fast without any overclocking.
The PowerColor HD6870 PCS+ is closer to the recommended price of $219, so you may consider it if you don’t need those overclocking technologies offered by MSI. We don’t want to blame the PowerColor version for its mediocre overclocking results because we might have just been unlucky to get a sample with low overclockability. The high level of noise of our sample is a far more serious problem but we don't know if such an aggressive setup of the fan management system is typical of all other samples of this card. Its cooler’s efficiency wasn’t high, either, perhaps due to poor contact between the heat pipes and the GPU or heatsink.
Thus, the MSI R6870 Hawk is the winner of our today’s fight. This Radeon HD 6870 version can be recommended for all AMD fans. It is just as good as the ASUS HD 6870 DirectCU and even more exciting than the latter in some respects. We are proud to award MSI R6870 Hawk with our Recommended Buy title: