Imagination launches PowerVR SGX
Unified shader architecture for mobiles
Imagination Technologies today launched its latest PowerVR graphics core design. The new release brings programmable shader support to the company's mobile graphics accelerator line-up.
The PowerVR SGX core - formerly known by its codename, 'Eurasia - provides shader support to beyond OpenGL 2.0 and DirectX 9 Shader Model 3 standard, Imagination claimed. The SGX's shader system, dubbed the Unified Scalable Shader Engine (USSE), merges vertex and pixel shading into a single pipeline capable of processing either kind of image element.
It's an approach adopted by ATI for its R500 Xbox 360 graphics chip and probably for the upcoming R520 desktop GPU. Nvidia is working on a unified shader architecture for its next-generation G80 GPU family. Like today's ATI and Nvidia chips, the SGX series employ their pixel processing pipelines to handle video work, including MPEG-4 and H.264 decoding and encoding, along with motion compensation and estimation, too.
The SGX architecture decouples geometry processing and rasterisation to achieve minimal stalling, along with on-chip support for multiple render targets (MRT). Non-visible pixels are not shaded leading to 2-3x fill rate compared to other solutions at the same bandwidth. The SGX series' effective fill-rate runs from 200m pixels per second to 1200mps at 200MHz, with even higher Z and stencil rates, Imagination claimed. Z and Stencil tests are performed on-chip requiring no external stencil or Z-buffer memory or bandwidth. Running through the range of core, polygon throughput is 2m polygons per second up to 13.5m at 200MHz. The core support colour precision up to 128 bits, and support multi-sampling anti-aliasing.
The SGX series will initially comprise three designs, the 510, 520 and 530. The cores range from 2-8mm², made possible in part by the USSE support for up to eight pipelines.
The SGX series builds on Imagination's existing PowerVR MBX line, itself founded on PowerVR's low-bandwidth tile-based rendering architecture and deferred pixel shading technique. The new cores are fully backward-compatible with applications developed for the MBX, Imagination said. The SGX family will not replace the MBX series, it said.
Like other PowerVR core designs, the SBX series will be made available to semiconductor makers under licence. Imagination said key licensees will receive their first core designs from Q4.
One such licensee is Intel, which said in May it had bought the rights to use the core design. It's already a PowerVR MBX licensee, using the technology in its PXA2700G mobile graphics chip, part of its XScale line-up.
In addition to Intel, Imagination has licensed PowerVR MBX to Sony Ericsson, Texas Instruments, Freescale, ARM - which also has the right to sub-license the graphics technology - Philips, Samsung and others. ®
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