Sapphire Tri-X R9-290X Review

👤by Richard Weatherstone Comments 📅12-08-14
GCN (Graphics Core Next)

The AMD Radeon R9 290X features an evolution of Graphics Core Next Architecture (GCN).
AMD has taken great strides to ensure that the GCN Architecture is capable of efficiently using its hardware resources. This seems like such a simple idea, but designing a GPU to frequently approach its peak theoretical performance is a challenge the GCN Architecture tackles with ease.

The GCN Architecture is designed for improved utilization, which ensures that the GPU is making optimal use of its resources for maximum performance.

The GCN Architecture also benefits from dramatically improved tessellation performance. Games featuring this DirectX® 11 technology are considerably faster than they were on the previous generation of AMD Radeon™ products. There is also the new Mantle API which promises to dominate NVIDIA, especially in titles such as Battlefield 4. Project Mantle is one of AMD’s most innovative and game-changing features, delivered with the Radeon™ R9 and R7 Series product line. Mantle is a new application programming interface (API), leveraging the commonality between the next-gen consoles and Radeon™. It enables game developers direct communication to our GPUs, unlocking the true potential of GCN and resulting in significantly higher gaming performance at all segments. We will be looking at Mantle in a separate article but if what we hear is correct, Microsoft (who are responsible for DirectX) should be very worried.

Every gamer knows that the GPU's clockspeed also has a big impact on the performance of a graphics card, and the GCN Architecture keeps that in mind.

But what many don't know is that every graphics card is designed to draw only a certain amount of power from your PC's power supply. This is called the Thermal Design Profile, or TDP, and it's critical that the GPU architecture is capable of making the most of every watt. The GCN Architecture can do that thanks to a technology called AMD PowerTune technology.

AMD PowerTune is an intelligent system that performs real-time analysis of the games and applications that utilize a GPU. Examples of such software might include Battlefield 3 or Furmark. In the event that an application is not making the most of the power available to the GPU, AMD PowerTune can improve that application's performance by raising the GPU's clockspeed by up to 30%! Best of all, this technology is completely automatic and is designed specifically to improve gaming performance.

Available on all 28nm AMD Radeon™ products, AMD PowerTune is designed to enable significantly higher clockspeeds in your favorite games-automatically!

The block diagram above shows us that the R9 290X has the following features:

Graphics Core Next Architecture
- Up to 44 Compute Units
- 4 Geometry Processors
- 64 Pixel Output/Clock
- 1 MB L2 cache
- 512-bit GDDR5 memory interface
- AMD TrueAudio technology
- New AMD CrossFire™ technology
- 6 AMD Eyefinity technology Display Controllers
- 6.2 billion transistors
- 28nm process node

The GPU has 4 shader engines, with each shader comprising of one geometry processor per shader engine which is load balanced with other shader engines on die. The 4x Geometry Processors feature a geometry assembler, a tessellator and vertex assembler. Performance is improved on the geometry shader and tesselation thanks to a reduction in off-chip bandwidth by LDS utilisation along with off-chip buffering.

The shader engine also features scalable compute resources with the new architecture supporting a possible 9 compute units. The instruction set and cache can be shared by up to 4 compute units each. The new GCN features 44 of these compute units equating to 2816 shaders on the 290X. In addition to the the scalable compute resources, there is one rasteriser unit per shader engine and 16 render back ends, each with 64b pixels per cycle and 256 Z/Stencil operations resulting in a massive pixel fill rate.

Finally, the GPU features asynchronous compute with up to 8 of these ACE per GPU. With independent scheduling and work item dispatch for ultra efficient multi tasking operations. Each ACE can manage up to 8 queues and has access to both L2 cache and GDS.

GCN Architecture is now the foundation of a common architecture that spans PC’s, next generation consoles and the new Mac Pro. The industry has spoken and resoundingly endorsed GCN for high performance graphics platforms.

Let’s take a look at some of the more familiar features of the Radeon card...

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