AMD Radeon HD 7970

AMD is using the Taiwan Semiconductor Manufacturing Companies new 28nm manufacturing process to build the new high-end Radeon HD 7970 GPU. The HD 7970 sports 4.3 billion transistors in a 365mm2 die. The 7970 supports OpenCL and OpenGL 4.2. It is assembled from 32 GCN compute units, which translates to 2,048 stream processors, each based on AMD’s new SIMD-plus-scalar architecture. As well, the 7970 includes 768KB of L2 cache and eight render back-ends, features a 384-bit interface to 3GB GDDR5 memory and a PCIe 3.0 interface.

AMD’s soon to become available Radeon HD 7970 graphics card seems to be a beast of an overclocker as recently two enthusiasts have managed to increase the card’s GPU clock from the standard 925MHz, to an impressive 1700MHz.



AMD took advantage of TSMC’s new 28nm manufacturing process to build its new high-end GPU. The Radeon HD 7970 sports 4.3 billion transistors in a surprisingly small 365mm2 die. AMD product marketing manager Devon Nekechuk tells us AMD’s 28nm yields have been both “good” and “predictable.”



Tahiti is assembled from 32 GCN compute units, which translates to 2,048 stream processors, each of which is based on AMD’s new SIMD-plus-scalar architecture. The existing Radeon HD 6970, by contrast, is equipped with just 1,536 stream processors and doesn’t benefit from the new architecture. The 7970 includes 768KB of L2 cache and eight render back-ends capable of pushing 32 color ROPs per clock and 128 Z/stencil ROPs per clock cycle. The existing 6970 provides the same quantity of render back-ends, but the newer card boasts higher throughput and much-improved efficiency; plus, the 7970 features a 384-bit interface to 3GB GDDR5 memory and a PCIe 3.0 interface. The GPU is capable of peak throughput of 264GB/s.

The semiconductor maker extends its GPU leadership with the AMD Radeon HD 7970 through AMD App Acceleration. This technology enables exquisite high-definition video images and exceptional performance improvements for everyday applications.

Also introduced in the card is AMD Eyefinity technology which enables gamers and desktop enthusiasts to connect up to six displays to one graphics card, delivering immersive stereoscopic 3D experiences and astonishing 16k x 16k display resolutions.

Being equipped with the latest PCI Express 3 standard, the card enables uncompromised image quality, and is additionally armed with GDDR5 memory, enabling accelerated GPU performance.

Based on intelligent AMD ZeroCore Power and AMD PowerTune technologies, the AMD Radeon HD 7970 enables higher performance levels while maximizing power efficiencies.

GCN marks a major shift in how AMD GPUs operate, behaving more like a general-purpose vector processor than a pure graphics engine. What’s more, each basic building block, called a GCN Compute Unit, includes a scalar coprocessor that can behave like a traditional—but non-pipelined—CPU. AMD has beefed up the caches that are distributed throughout the GPU. Each GCN core (yes, AMD is calling them cores) has its own dedicated L1 read/write cache. Each group of four cores shares a 16KB instruction cache and a 32KB scalar data cache. All the cores communicate over a shared bus to a partitioned L2 cache that can be sized differently depending on the graphics card and particular GPU die.
AMD intends for GCN to serve as the basis for several product families. The first product, code-named Tahiti, is aimed at gaming enthusiasts who want maximum frame rates while enabling maximum eye candy. The next product, code-named Pitcairn, will supersede the Radeon HD 6800 series. Pitcairn will be followed by a series code-named Cape Verde, which AMD believes will redefine the segment now held by products such as the Radeon HD 6700 series


Benchmarks
AMD Radeon HD 7970 ReferenceXFX Radeon HD 6970EVGA GTX 580 SCEVGA GTX 580 Classified3DMark 2011 Perf7,9855,7506,7477,3213D Mark Vantage Perf31,87324,45326,93628,559Unigine Heaven 2.5 (fps)28172223Shogun 2 (fps)28192224Far Cry 2 / Long (fps)96758592HAWX 2 DX11 (fps)11373120128STALKER: CoP DX11 (fps)37252829Just Cause 2 (fps)48314148Batman: Arkham City (fps)51364547Metro 2033 (fps)17141517DiRT3 (fps)60445055Core /Memory Clock Speeds925 / 1375880/ 1375797 / 1013855 / 1053Power @ idle (W)124126140140Power @ full throttle (W)325*296344385Price$549$350$550$600* "Long dark" system power was 109W
Best scores are bolded. Our test bed is a 3.33GHz Core i7 3960X Extreme Edition in an Asus P979X Deluxe motherboard with 16GB of Corsair DDR3/1600 and an AX1200 Corsair PSU. The OS is 64-bit Windows Ultimate. All games are run at 2560 x 1600 with 4x AA, except for the 3DMark tests.