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AMD Radeon HD 7950 Review; Tahiti Pro Arrives

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SKYMTL

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More HD 7950 Launch Coverage:

- XFX HD 7950 Black Edition DD review HERE
- Sapphire HD 7950 Dual Fan OC review HERE



With the launch of their Southern Islands architecture, AMD proved they still have what it takes to engineer a class leading graphics core. The 28nm Tahiti XT core which graced the flagship HD 7970 packed 4.3 billion transistors into a compact, efficient design and easily wrested the “fastest single GPU” title away from NVIDIA’s GTX 580. Initial availability may not have been quite up to some people’s expectations and the cards did run a bit loud (an issue which has supposedly been corrected on the retail products) but otherwise, we felt it was a nearly perfect graphics card.

The HD 7970’s $549 price point may have been firmly targeted towards certain well heeled gamers but AMD’s encore presentation is aimed at much larger audience. By taking the same Southern Islands architecture and essentially cutting it down in a few key areas, we now have the Tahiti Pro and a new graphics card: the HD 7950 3GB. This unassuming product holds a key place in AMD’s current lineup since it is supposed to compete against the GTX 580 while offering lower power consumption, less heat production and a highly competitive price of $449. Now $449 may still put the HD 7950 far above most people’s modest budgets but it does make this new generation of GPUs accessible to a wider market.

A move away from a VLIW core layout has allowed the Southern Islands cores to grow beyond the limitations of past architectures and the HD 7950 is no different in that respect. Much like its bigger brother, it incorporates several key technological advances which are supposed to increase rendering throughput, optimize DX11 application performance and it should be able to vastly outstrip the previous generation in compute-related tasks. Naturally, scaling back on some parts of the architecture will lead to lower performance than its $550 sibling but we’re still expecting great things from this launch.

Before moving on in this review, let’s attack the million dollar question head on: what will availability be like? AMD actually surprised us by attaining reasonable stock levels of most key HD 7970 SKUs from its launch day onwards. While we may have some cautions optimism this time around, hopefully launching in the midst of a Chinese New Year won’t have an adverse effect upon long term availability.

The new HD 7950 3GB is looking to fill a key hole in a busy lineup and with a price of $449 it should offer an excellent mix of performance and efficiency for gamers who use higher end systems. If AMD has hit their performance just right, for the time being NVIDIA may not have a anything that can compete on a level footing against this new card.

 

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Graphics Core Next: From Evolution to Revolution

Graphics Core Next: From Evolution to Revolution


Much like the outgoing Cayman series of cards, Tahiti is focused upon improving AMD’s position within a highly competitive (and lucrative DX11) market. Though previous generations like the HD 5000 and HD 6000 relied largely upon a core architecture that existed since 2006, the next iteration of parts will have a new design that has been engineered from the ground up for DX11 and compute environments. However, in order to see where AMD is going, you have to understand what they’re coming from


AMD’s graphics cores have always had fairly long lifespans and that says a lot about how they have usually designed the best possible architecture for a given generation. While this approach certainly has benefits from a financial and planning perspective, introducing the wrong architectural design can have long term consequences.

The first era of modern GPUs ran from 1998 through 2002 and introduced us to fixed function rendering which worked well for the time but featured limited the ways to do geometry, lighting and texturing. Even though modern graphics architectures still have a fixed function stage containing the geometry processing elements, these have now been incorporated into a much larger rendering picture.

AMD’s second round of designs ushered in the revolutionary DX9 era along with its accompanying generation of products. It featured the beginning of programmable rendering pipelines and new pixel rendering functionality while laying groundwork for the DX10 and DX11 products to come. Meanwhile, the release of DX10 in 2007 meant the introduction of unifed shader units and the VLIW (Very Long Instruction Word) architecture for parallel core operations. AMD has adhered to the VLIW approach for a while now and as DX10 gave way to DX11, additional functionality and minor modifications were gradually built in.

In a roundabout way, this brings us to AMD’s new take on both graphics and parallel computing called Graphics Core Next or GCN. This may not carry the most unique of names, it outlines what this new architecture means for AMD: a true next generation approach. Simply put, it was high time for a change away from VLIW in order to bring intergenerational performance up to the industry’s expectations. GCN also represents the first steps towards a truly heterogonous environment between the CPU and GPU since it will eventually be an integral part of AMD’s upcoming APUs.


The fundamental building block for all things GCN is called the Compute Unit. In layman’s terms this is a compact, self contained building block of sorts that was designed to increase on-die content flow efficiency by keeping much of the data local rather than handing it off to a global shared stream. For example, the previous generation’s SIMD array, compute unit, registers and cache all fed off the same thread sequencer and had to share resources in a complex dance of information. Each Compute Unit is treated independently and allows for the SIMD communications, sequencing and scheduling to be run in a single cohesive structure before handing it off.

From a thread processing standpoint a single Compute Unit has 4 sub Vector Units (or SIMDs) made of up 16 Stream Processors each for a total of 64 cores per CU. This layout is backstopped by a quartet of Texture Units and 16KB of dedicated read / write L1 cache. The amount of L1 cache doubles the amount from previous architectures so instead of reading textures and exporting raster functions to an external memory buffer, these instructions can now be sent to the local cache instead.

With the Vector Units producing their own independent streams, it was important to include a high bandwidth scheduler. The Scheduler works alongside the unified cache and the 64KB of local data share to facilitate the information flow between data lanes. In the Queen’s English, it acts like a traffic light to direct data towards a set location.

Another important part of the Compute Unit’s hierarchy is the inclusion of a dedicated Scalar Unit with its own registers. This unit acts like a general purpose programmable core that can issue its own instructions and can take part of the workload off of the other areas of the Compute Units or can work independently if need be. Think of it as a central processing unit within each cu.


As you can see above, the move away from a VLIW4 SIMD architecture towards Stream Processors contained within four distinct separate Vector Units significantly increases on-die efficiency. The “Quad SIMD” approach is able to process information on a parallel basis without any potential conflicts in the data stream, thus speeding up data hand-offs and increasing overall performance per square millimeter.


Backing up the Compute Units is an expanded and very robust caching design that is linked together by the Global Data Share. While the Global Data Share is the glue that binds communications between CUs together, it can also take some heat off the L2 cache by managing all on-chip data sharing services.

In addition to the aforementioned L1 cache, each quartet of Compute Units has access to 16KB of instruction cache and 32KB of scalar data cache which are both helped out by the L2 cache units. Speaking of the L2 cache, AMD has upped the ante here as well with twelve partitions of 64KB for a total of 768KB.
 

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Increased Geometry Processing & ROP Efficiency

Increased Geometry Processing & ROP Efficiency



Look familiar? Upon first glance there really isn’t all that much different between the geometry processing engines in the current and next generation architectures but there are several optimizations built in for increased efficiency and throughput.

Let’s start with the obvious first. Much like Cayman, Tahiti uses two distinct geometry processing engines that are accessed through a common Command Processor which takes care of load balancing and scheduling. The fixed function stages are broken up into the two engines that work in parallel and contain what AMD calls their “ninth generation” tessellators. Alongside other small changes, these new tessellation units still feature off-chip buffering which allows geometry data from tessellated workloads to be stored in the DRAM if the on-chip cache becomes saturated. However, due to the large amount of fast L2 cache available in the Tahiti core, tessellation performance has been increased by an order of magnitude over Cayman.


The result of these changes to the tessellation engine is a vast improvement over the HD 6900-series at higher levels of tessellation. Many people may clue into the seemingly lackluster increase at lower levels but we have to remember that the previous architecture already brought a ton of potential to the table in exactly these situations. Once everything is taken into account, Tahiti should offer more balanced performance in DX11 games that demand all levels of geometry processing.


Once again there really doesn’t seem to be much in the way of changes to the ROP layout either with partitions of four ROPs and 16 z-stencil units throughout the core. However, AMD makes better use of these ROPs by leveraging Tahiti’s increased memory bandwidth for a 50% theoretical fillrate increase over the previous generation.
 

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The Tahiti Pro Core Uncovered

The Tahiti Pro Core Uncovered



Once we bring together the items we have seen on the last few pages, a clearer picture of the Tahiti core begins to emerge. From a high level standpoint there are quite a few similarities between the outgoing and incoming core layouts but the functionality introduced by the Graphics Core Next architecture makes this a whole new ballgame.

Let’s start with the basic Graphics Core Next design elements since that is where most of the advances lie. The “core” of the fully enabled Tahiti core houses 32 Compute Units broken up into two engines of 16CUs each. If you remember our previous discussions, each one of those CUs houses four SIMDs with 64 cores and four texture units for a total of 2048 Stream Processors and 128 TMUs in a fully enabled Tahiti XT core. When this ~500 SP and 32 TMU increase over Cayman is combined with GCN’s new Compute Unit processing features, AMD claims a 40% increase in compute and texture fillrate performance from one generation to the next.

The Tahiti Pro meanwhile uses all of the same elements as its big brother but has four Compute Units disabled. The result is a 1792 core, 112 TMU part that still retains an identical number of ROPs, tessellators, cache and memory controllers as the Tahiti XT so performance shouldn’t take a massive hit in every application.

While the main core elements have changed drastically, items like the Geometry Engines and render backends haven’t seen much in the way of architectural changes and some may even think they have been overlooked. There are still eight combined Render Output Units which hold four ROPs each, giving the Tahiti core a maximum of 32 ROPs, or exactly the same number as Cayman. Granted, the shared L2 cache and additional memory bandwidth does help these attain an approximate 5% real world increase in pixel fillrate but that’s not much considering the improvements apparent elsewhere.

The Geometry Engines house the most critical parts of any DX11 architecture and while it looks like AMD hasn’t done much here, we can’t forget that Cayman already incorporated several key advances in DX11 processing. Nonetheless, there have been some fancy moves going on behind the scenes with the two tessellators being upgraded, increasing their theoretical throughput.


Moving down to the “lower” part of the Tahiti block diagram we come to the L2 cache and memory controllers, both of which have seen a fundamental evolution away from previous designs. Instead of being incorporated into four distinct blocks and being tied to the Render Backends, the full amount L2 cache is now shared throughout the core and scales independently from the ROPs and memory controllers. It has also been doubled in size to 768KB, ensuring there is enough for storing information on the fly.

The GDDR5 memory controllers don’t feature any behavioral differences from the ones found on Cayman but two additional 64-bit units have been added to make a 384-bit interface which powers up to a dozen modules. As we already mentioned, they have been decoupled from the rest of the architecture so in theory we could see a 384-bit card with less ROPs than the fully endowed version of Tahiti.
 

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Tahiti as a Compute Powerhouse

Tahiti as a Compute Powerhouse


Graphics processing may be what most of us will use AMD’s new architecture for but it has also undergone a thorough revision on the compute side as well. Once again the Compute Units sit at the heart of the equation when running computational algorithms but with the rendering pipeline out of the way, things are done quite a bit differently. We should also mention that AMD has built in native support for Open CL 1.2, DirectCompute 11.1 and C++ AMP as well.


The Tahiti core makes use of two Asynchronous Compute Engines which can run parallel compute pipelines independently from the graphics rendering pipeline. In short this means compute and graphics applications can be run at the same time, though with reduced resources in both situations. A new DMI engine has also been implemented which is designed to take advantage of the massive amount of bandwidth PCI 3.0 offers between the GPU and the CPU. According to AMD, the dual DMI Engines can essentially saturate the full bandwidth of a Gen 3 x16 slot.

By adding ECC support on both internal and external memory AMD has also increased this core’s appeal for the HPC crowd. We’ll be covering the full benefits of the new GPGPU processing engine in a future article.


The Tahiti core may boast 4.31 billion transistors but one of AMD’s main focuses has been to fully utilize their core at all times. Since every aspect of the core architecture can process parallel data flows with independent scheduling, AMD has realized vastly improved performance per square millimeter without blowing power consumption out of the park.
 

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PowerTune Technology / ZeroCore Power

PowerTune Technology


One of the largest challenges GPU manufacturers face is the rapid increase in the power consumption of their higher-end ASICs. NVIDIA’s solution to cut consumption and TDP in their GTX 500-series was a combination of input current monitoring and upgraded heatsinks along with application detection. AMD meanwhile took a different path with their PowerTune technology. It uses a complex set of concurrent calculations to determine on-the-fly TDP levels so clock speeds can be adjusted once the card reaches a pre-determined maximum thermal design power level.

The entire point of PowerTune is to allow AMD to strike a delicate balance between power consumption, thermals and clock speeds. If such a middle-man didn’t exist, the clock speeds many AMD GPUs would have been significantly lower since there would have been nothing to keep TDP in check. As one might expect, PowerTune makes a comeback for the Tahiti cores and it still behaves in the same way as before.


A typical GPU will likely be used in any number of applications but its primary focus will usually be upon one thing: entertainment. While there are several synthetic benchmarks which cause a graphics card to consume copious amounts of power, most typical games will never even begin to approach these levels. As such, AMD has focused their PowerTune technology upon scenarios which put unrealistic loads upon the GPU rather than games. Since most of us don’t sit around all day benchmarking with 3DMark, this is good news.

Unfortunately, depending on their rendering methods there may still be the odd game which will be caught up in the crossfire and have its performance capped but we will be tackling this potential issue in a later section. It is just important to remember that AMD has tuned this technology to deliver the best gaming performance while weeding out potential power viruses.


As AMD describes it, this new technology is simply used to contain power consumption in such a way that the actual TDP of a given product will in effect determine clock speeds. Instead of letting the card run amok for the few seconds of absolute peak consumption that will likely occur every now and then, PowerTune caps power draw through clock speed modification. After the peak periods are concluded, clock speeds along with performance will return to normal.


This may all sound like doom and gloom for overall performance but PowerTune is actually designed for a worst-case scenario rather than a typical usage pattern. The algorithm to determine implied power consumption is based upon an extremely high leakage ASIC operating with 45 degree inlet temperature. Remember that high temperatures increase power draw in transistors so this ensures products are not artificially capped in lower temperature scenarios. Since TDP is the determining factor here, if you keep your card cool within a well ventilated case you should in theory never see PowerTune kick in while gaming. According to AMD, it has also allowed them to drastically increase the clock speed of their cards since PowerTune allows for better TDP predictability.


ZeroCore Power



Another feature AMD is introducing with the Tahiti core is called ZeroCore Power. If you are someone who leaves their computer on for long periods of time or intend on running a multi card setup, pay special attention to this section.

One of the issues with most modern graphics cards is their power consumption when not actively driving 3D graphics content or accelerating certain applications. Even if your monitor is turned off, the only way of conserving electricity is to put the system to sleep or allow it to hibernate. Granted, when in idle mode a GPU doesn’t consume all that much power but a constant 30W over long periods of time can sure add up on a monthly power bill. This is where ZeroCore Power steps into the equation.

The basic idea behind ZeroCore Power is to effectively shut down the card during periods when the GPU isn’t outputting an onscreen image. These “long idle situations” are determined by Windows which is programmed to shut off your display after a preset amount of time (you can access it by going into the Display Power Options and choosing when Windows can turn off your display) in order to optimize full system efficiency. AMD’s driver will detect this and put the graphics card into a suspended sleep mode by shutting off the fan and powering down non-essential onboard components. It will then wake back up the moment Windows detects an input and activates the display again.

According to AMD, ZeroCore Power allows a Tahiti-based card to drop down to about 3W during these long idle situations which is a vast improvement over Cayman’s ~30W consumption.


Where ZeroCore Power technology really comes into its own is in Crossfire setups. Since only one GPU is driving the display at all times, any additional cards are automatically put into ZeroCore mode, even when in standard idle conditions. The result is drastically lower idle power consumption numbers for systems with more than one GPU. Meanwhile, in long idle situations, even the primary graphics card is put into a suspended sleep mode as well.

AMD hasn’t stopped there either. Tahiti has features power saving features like engine clock deep sleep and a DRAM stutter mode (which compresses any residual contents within the framebuffer) in order to further reduce standard 2D power consumption to a mere 15W. If you add this all up, a triple Crossfire setup will consume just 21W when in idle 2D mode (15W for the primary card and 3W for each additional card) compared to about 90W for a 3x HD 6970 configuration. In our opinion, this could be a game changer for any holdouts who couldn’t justify more than one GPU due to excess power consumption and heat production when not gaming.
 

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Advanced Image Quality & Partially Resident Textures

Advanced Image Quality


Much has been said about AMD’s claims of leading edge texture filtering quality on the HD 6000-series but for the most part, it was an improvement over previous generations. Whether it was up to expectations is still open for debate but the Southern Islands family is once again claiming to have virtually eliminated the flickering and artifacts that sometimes appear in games.


In order to high the high note in terms of texture filtering, Southern Islands cards feature an improved anisotropic filtering algorithm that’s designed to virtually eliminate shimmering in high resolution textures. This may sound like a tall order to fulfill but after seeing it in action, we’re confident AMD can deliver this time around.

One of the beauties of this new filtering algorithm is its ability to run without additional buffering so there is no drain on system resources. In addition, it is automatically enabled to gamers should see vastly improved image quality without having to dive into the Catalyst Control Panel.


Introducing PRT (Partially Resident Textures)


One of the main challenges for today’s GPUs is how to handle large amounts of high resolution textures when moving through a scene. Presently, when a player moves through a game environment the texture information in upcoming frames is constantly loaded between the disk, CPU and the graphics card. Usually the effect of this preloading is seamless but as larger amounts of information are loaded, stuttering can occur.


AMD’s solution to this somewhat complex problem is to leverage the local memory on the GPU and allow it to act as a true texture caching system. Essentially, upcoming textures are prefetched from the CPU and disk and stored locally on the GPU until they are ready to be used by the application. In a way this can almost be considered a form of texture “streaming” and should help eliminate the stutter normally associated with scene loading.


In addition to preloading, PRT can also dynamically load selected textures based on when they will be needed instead of loading every bandwidth-hogging texture all the time. This should help eliminate the memory footprint the feature requires.

Unfortunately for gamers Partially Resident Textures technology is application controlled so it has to be built into a game engine before it can be utilized. Supposedly, AMD’s development team is working with game developers to include this feature in upcoming releases but there aren’t any titles on the horizon that will put it to good use.
 

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Eyefinity 2.0 / UVD3 & VCE

Eyefinity 2.0


When Eyefinity was first introduced, it caused some serious waves in the industry since it was the first standard to properly support multi monitor setups. Since then it has gradually evolved alongside NVIDIA’s Surround technology to become a must have for gamers who want the most immersive experience possible. In the last few months have brought about a number of advancements for Eyefinity users and the beginning of 2012 will also hold some great steps forward as AMD transitions to Eyefinity 2.0.


October 2011 showed us the first steps towards the “2.0” ecosystem as a number of new features were rolled out. Support for 5x1 portrait and landscape setups saw the light of day for those of you with truly massive desks and the much requested support for flexible bezel compensation was included as well. Finally, support for very well-heeled gamers came in the guise of full 16k resolution support.


Catalyst 11.12 didn’t roll out anything revolutionary for Eyefinity other than support for full stereoscopic images over multiple panels via AMD’s open HD3D standard. Meanwhile, the 12.1 software stack should include Crossfire profiles for Eyefinity + HD3D setups


The February 2012 drivers will also herald some additional features like custom resolution support and improvements to Catalyst’s Eyefinity preset manager. Last but not least we should also see the first implementation of automatic taskbar repositioning which will place your desktop icons and Windows taskbar on the center monitor for a more convenient setup.



UVD3 & VCE



When the HD 6900-series was first shown off to the world, it included AMD’s third generation Universal Video Decoder. One of its main features was its ability to decode videos which use MVC encoding. As part of the H264 / MPEG-4 AVC codec, MVC is responsible for creating the dual video bitstreams which are essential for stereoscopic 3D output. Supporting this standard brought AMD’s GPUs the ability to process Blu-ray 3D movies through a HDMI 1.4a connector. MPEG-4 Part 2 hardware acceleration for DivX and Xvid codecs was also added. With all of that being said, the Southern Islands-based cards continue to use the UVD3 standard as its base functionality was forward looking enough that additional features weren’t needed.


When compared to UVD3, AMD’s new Video Codec Engine is a different beast altogether. The VCE is essentially a one stop shop for hardware encoding via the GPU’s compute engine and provides a highly parallel scalable pipeline for many high definition tasks. It can also provide additional benefits for transcoding and output tasks.
 

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AMD’s Current and Upcoming Lineup under the Microscope

AMD’s Current and Upcoming Lineup under the Microscope



Now that the sticky and complicated architectural lecture is out of the way, its time concentrate on the HD 7900-series’ position in AMD’s current lineup. Let’s start with the obvious part first: the Tahiti is supposed to steamroll Cayman in every way possible. At 4.3 billion transistors, this is by far the most complex core AMD has engineered but due to TSMC’s 28nm manufacturing process, power consumption has remained at approximately the same level as the previous generation. These new cores also come with full compatibility for DX11.1 (which will be available with Windows 8) and the bandwidth provided by PCI-E 3.0.

From a purely specifications standpoint, the previously introduced HD 7970 has nearly 40% more Stream processors and 32 additional TMUs when compared against its predecessor while the engine clock gets a boost to 925MHz. While the ROP count doesn’t receive much –if any- attention, the higher core speed means throughput has nonetheless been increased from one generation to the next. 4.3 billion transistors, 3GB of GDDR5 and an advanced manufacturing process certainly doesn’t come cheap though, making the HD 7970 the most expensive single GPU card from AMD in recent memory. However, while the Tahiti XT-based card may look pricy when compared to the rest of AMD’s lineup, it actually compares quite well to NVIDIA’s current single GPU flagship; the GTX 580.

However the subject of this review is the less expensive HD 7950, a card that slots in between the soon to be EOL’d HD 6970 and the current single GPU flaghip. In order to achieve a lower price point but still retain great performance results, it uses the Tahiti XT core as a foundation but has a few elements pared down. Instead of 2084 cores and 128 texture units, the Pro model uses 1792 Stream processors and 112 TMUs spread across 28 compute units. To differentiate itself even more from its higher end sibling memory and core clocks have been reduced by about 10% in both cases.

There are however some remnants from the flagship card since the HD 7950 retains the same number of ROPs and 3GB / 384-bit memory layout as the Tahiti XT. Not only will this allow AMD’s newest card to excel in DX11 games but in ultra high resolution scenarios, the extra bandwidth should allow this card to pull far ahead of NVIDIA’s offering. Speaking of the compeition’s flagship single core product, with a price of $449 the HD 7950 is obviously meant to go up against and thoroughly defeat NVIDIA’s GTX 580.


There is a whole lineup of next generation parts in the pipeline that begins with the HD 7970 and the HD 7950. Slightly further down the product stack is Pitcairn, an architecture which should play a role near and dear to most gamers’ hearts since it will take over the highly popular $199 to $299 market from the HD 6800 and HD 6950 cards. Finally, there’s Cape Verde. This small, efficient GPU is billed as the spiritual successor to the highly successful HD 5700 and HD 6700 cards.

With Tahiti, Pitcairn and Cape Verde all on their way, AMD surely has their hands full but there’s one other wrinkle in the fabric of this story: they’ll all be launching alongside a dual GPU product…….before the end of Q1 2012. That means by the time April hits we could conceivably see four new families of AMD GPUs hitting a minimum of seven different price points. Whether or not they’ll all be hard launches is anyone’s guess but regardless of availability, the first half of 2012 will continue to be a great time for graphics card shopping.
 

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A Closer Look at the HD 7950 3GB

A Closer Look at the HD 7950 3GB



Look familiar? From a visual perspective the reference HD 7950 we were given is the HD 7970’s doppelganger. It sports an identical length of 11” and the same glossy black and red heatsink shroud which is backed up by a typical blower-style fan setup. This commonality between AMD’s two highest end Southern Islands cards shouldn’t come as a surprise since reusing the same components allows for a good amount of cost savings. But as we will see on the next page, board partners have been given the freedom to design their own versions of the HD 7950.


The outside design is identical to the Tahiti XT card and those similarities carry on to the areas under the heatsink as well. The HD 7950 still uses an extensive vapor chamber cooler that should help it stay cool without necessitating high fan rotational speeds. It also features a dual BIOS switch to change between the default BIOS and a user-defined custom profile that can hold anything from higher voltage settings to preset overclocks and fan speeds.

One difference we can see is a direct result of the more efficient and cut down core design: there are two 6-pin connectors in the place of the HD 7970’s 8-pin / 6-pin setup. Regardless of this change, the reference card’s PCB still has the pin-outs necessary for a dual 8-pin layout and we’re sure some board partners will take advantage of this in future designs.


As we already mentioned, AMD seems to have used the same basic reference PCB design for both the Tahiti Pro and XT. Supposedly even the VRM layout is carried over from the higher end card but remember that board partners may or may not choose to incorporate this (supposedly) expensive component set. For simplicity’s sake it is likely that the first few batches of HD 7950 cards will use the core agonistic layout we see here but as volume picks up and prices decrease changes will gradually be made.


You guessed it: the backplate is identical to the one found on the HD 7950’s sibling with a pair of mini DisplayPort connectors, an HDMI output and a lone DVI. While most board partners should be shipping cards with a single mini DP to DP adaptor and a HDMI to DVI break out cable (which can allow the HD 7950 to natively support Eyefinity configurations), we have seen some instances where bundles have been cut down and won’t include either additional connector.


As you can see, the HD 7950 is about the same length as a GTX 580, give or take about a quarter of an inch.
 
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