ATI Radeon’s next flagship is all set to target Q2 2012.
The ATI Radeon 7k series codenamed Southern Islands are expected to be based on something known as the VLIW4 (Very Long Instruction Word ) SP arrangement circuits. The same circuitry is used in the high end HD 6900 series. FYI the HD 6800 Series were based on VLIW5 arrangement. Theoretically both architectures provide similar computation power, VLIW4 providing reduced die size. Without jumping further, lets see whats this VLIW4 is?
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VLIW4 is a chip architecture, you can say it is the GPU technology architecture. In VLIW4 where the number 4 (of VLIW4) means group of 4 SP’s (or 4 SIMD processor) which form a functional unit or AMD Radeon cores (Math units) of this new circuit architecture. All 4 SP’s have same computational potential. However, two of the SP’s especially every 3rd and 4th SP in the group has some special function which is currently unknown, but it may be used for scheduling other SP’s in the group. In 7k series, each SIMD will now be able to perform two GPE’s (Graphics Processing Engine) Cycle. This means almost 3-4x performance increase is expected as compared to the current generation one’s. VLIW designs are unique and are designed to execute many operations from the same task in parallel by breaking it up into smaller groupings called Wavefronts (In case you are wondering about NVIDIA, this is same as CUDA cores /WARP). In AMD’s case a wavefront is a group of 64 pixels/values (A warp on the other hand is 32-bit) and the list of instructions to be executed against them. Ideally, in a wavefront a group of 4 or 5 instructions will come down the pipe and be completely non-interdependent, allowing every Radeon core to be fed. [Read More at @nandtech]
While 7k series will be based on VLIW4, HD7900 will built on a different technology, a stepping stone for AMD’s GPU architecture called as GCN.
GCN (Graphics Core Next) Architecture
ATI brings in the Graphics Core Next (GCN) which is the architectural basis for AMD’s future GPUs, both for discrete products and for GPUs integrated with CPUs as part of AMD’s APU products. AMD will be introducing a major overhaul of its traditional GPU architecture for future generation products in order to meet the direction of the market and where they want to go with their GPUs in the future. The main focus is on the compute capability of the GPU’s targeting towards high performance computing for enterprise markets where precision is a key. The GCN is completely a non-VLIW4 architecture, means that the architecture will be focusing completely on the threads now instead of instructions. To be precise, the non-VLIW4 SIMD would run parallelism at thread level also known as the TLP (Thread Level Parallelism), the one which NVIDIA follows. The new 7k series with GCN architecture would be able to perform double precision floating point operations i.e FP64. There’s more to it.
Leaked Specification ATI Radeon HD 7k Series
For the first time, ATI GPU’s higher end 7k series 7970 and 7950 will harbor XDR™2 memories. The XDR™2 memory architecture is the world’s fastest memory system solution capable of providing more than twice the peak bandwidth per device when compared to a GDDR5-based system. Further, the XDR 2 (2005 by RAMBUS) memory architecture delivers this performance at 30% lower power than GDDR5 at equivalent bandwidth.
Click here to go to RAMBUS XDR™2 Page
XDR™2 will provide high-performance to gaming, graphics and multi-core compute applications. Each XDR 2 DRAM can deliver up to 80GB/s of peak bandwidth from a single, 4-byte-wide, 20Gbps XDR 2 DRAM device. With this capability, systems can achieve memory bandwidth of over 500GB/s on a single SoC. Watch to know more.
AMD launching the Southern islands in 2012 Q2 seems very exciting. AMD will be launching its 7k series with the 28nm GPU with VLIW4 and will later introduce the Graphics Core Next. With the advancement and more and more opting of DX11, 7k series would definitely accelerate the current tessellation performance and mostly the long awaited GPU Compute Capability.