With the initial release of the 7900 series AMD moved away from the VLIW5 and VLIW4 architecture we have seen in the last generation of products. If anything, VLIW4 has shown certain inefficiencies in the Radeon HD 6900 series and while VLIW designs are fine for graphics they are not so grand for computing.
The Radeon HD 7700 series is also based on the GCN architecture.
GCN is short for Graphics Core Next architecture and the architecture building block has changed significantly to remove certain inefficiencies seen in the VLIW architecture.
A GCN in essence is the basis of a GPU that performs well at both graphical and computing tasks. For the compute side of things the new GCN Compute unit model has been introduced, it is designed for better utilization, high throughput and multi tasking, e.g. performance, performance, performance.
So your basic new Shader cluster is one called a (GCN) Compute Unit:
16 wide SIMD units
64 KB registers / SIMD unit
Now if we take 4 of these SIMD units that will be the basis of one Compute Unit (CU), each SIMD unit is 16 wide, times four per compute unit means that each CU has 64 shader processors.
The Cape Verde GPU has 10 Compute Units meaning 64SIMDs x 10 CUs = 640 Shader processors (for the R7770).
Engine has Dual Geometry engines / Asynchronous Compute engines
32 color ROPs per clock cycle
Engine ties to 512KB R/W L2 cache
Cape Verde GPU has up-to 10 Compute Units
The Graphics Core Next Compute Unit (CU) has about the same floating point power per clock as the previous one (i.e. Cayman). It also has the same amount of register space (for the vector units). Each CU also has its own registers and local data share.
GCN is more efficient since it does not require instruction level parallelism (we assume it costs some more area/transistors as well). The outcome, compiling also becomes much more uncomplicated and that means more efficiency and thus there it is again, better performance. GCN is all about creating a GPU good for both graphics and computing purposes.
AMD Radeon R9 NANO review Small, tiny and cute are the keywords for the AMD Radeon R9 Nano that we review today. The product has an incredible small form factor yet is powered with a Fiji XT chip that bring some significant gaming performance to this graphics card.
AMD Radeon R9 NANO preview At the launch of the Radeon R9 Fury and Fury X AMD also announced something that caught the interest of many, a small form factor yet high-end graphics card aimed at powerful small game and HTPCs, yes...
AMD Radeon R9 Fury X review We review, test and benchmark the Radeon R9 Fury X, one of the most discussed products of the year. A product that is big in performance, comes with that all new HBM memory and is based on a small for...