AMD 7xxx Series Graphics

The Southern Islands series is a family of Radeon GPUs developed by AMD. AMD builds Southern Islands series graphics chips based on the 28 nm manufacturing process at TSMC.

In 2010, the Northern and Southern Islands cards adopted the AMD Radeon brand name. Southern Islands GPUs are branded as the Radeon HD 7000 Series.

[edit]Technical details

• Support for x86 addressing with unified address space for CPU and GPU.
  • 64-bit addressing
  • Support for PCI-E 3.0
  • GPU sends interrupts to CPU on various events (such as page faults).
• Usage of RISC SIMD instructions for GPGPU instead of VLIW MIMD (Which was only one option in previous AMD GPU-architectures).
• Support for Partially Resident Textures, which enable virtual memory support through DirectX and OpenGL extensions.
• PowerTune support, which dynamically adjusts performance to stay within a specific TDP.
• Usage of Liquid-chamber cooling technology over Vapor chamber.

These changes could lead to better utilization of the GPU for compute along with traditional graphics.

It is noteworthy that, as opposed to the Evergreen and Northern Islands GPU Families, the Southern Islands GPU Family has only 4 chips instead of 5, omitting the lowest end one (resp. Cedar and Caicos in previous families). This is due to this segment now being served by GPU cores integrated into AMD's CPUs.

Products

The 28 nm product line is divided in three dies (Tahiti, Pitcairn, and Cape Verde), each one roughly double in shader units compared to its small brethren (32, 20, and respectively 10 GCN compute units). While this gives roughly a doubling of single-precision floating point, there is however a significant departure in double-precision compute power. Tahiti has a maximum 1/4 double precision throughput relative to its single precision throughput, while the other two smaller consumer dies can only achieve a 1/16 ratio. While each bigger die has two additional memory controllers widening its bus by 128 bits, Pitcairn however has the same front-end dual tesslator units as Tahiti giving it similar performance to its larger brethren in DX11 tesselation benchmarks.

[edit]Radeon HD 7900

Codenamed Tahiti, the Radeon HD 7900 series was announced on December 22, 2011. Products include the Radeon HD 7970 and Radeon HD 7950. The Radeon HD 7970 features 2048 usable stream cores, whereas the Radeon HD 7950 has 1792 usable stream cores, as 256 out of the 2048 cores are disabled during product binning which detects defective areas of a chip. The cards are the first products to take advantage of AMD's new "Graphic Core Next" compute architecture. Both cards are equipped with 3 GB GDDR5 memory and manufactured on TSMC's 28 nm process.

[edit]Radeon HD 7800

Codenamed Pitcairn, the Radeon HD 7800 series was formally unveiled on March 5, 2012 with retail availability from March 19, 2012. Products include the Radeon HD 7870 and Radeon HD 7850. The Radeon HD 7870 features 1280 usable stream cores, whereas the Radeon HD 7850 has 1024 usable stream cores. Both cards are equipped with 2 GB GDDR5 memory and manufactured on TSMC's 28 nm process.

[edit]Radeon HD 7700

Codenamed Cape Verde, the Radeon HD 7700 series was released on February 15, 2012. Products include the Radeon HD 7770 GHz Edition and Radeon HD 7750. The Radeon HD 7770 GHz Edition features 640 usable stream cores, whereas the Radeon HD 7750 has 512 stream cores based on the GCN architecture. Both cards are equipped with 1 GB GDDR5 memory and manufactured in 28 nm.