by Anton Shilov
01/02/2014 | 11:50 PM
In a bid to improve production yields of highly-complex central processing units (CPUs) and graphics processing units (GPUs) their developers integrate more execution units than is needed to meet performance goals. For example, system-on-chips for new-generation consoles have redundant graphics processing compute units. Moreover, AMD’s latest code-named Hawaii graphics processors may feature more stream processors than officially advertised.
Advanced Micro Devices today sells two graphics cards based on Hawaii GPUs: the Radeon R9 290X (configured to feature 2816 stream processors [or 44 compute units [CUs]], 176 texture mapping units [TMUs] and 64 raster operating units [ROPs]) as well as Radeon R9 290 (2560 stream processors (40 CUs), 160 TMUs and 64 ROPs). AMD has not formally announced specification of a fully-unlocked Hawaii graphics chip; moreover, the company has never demonstrated a die-shot of the GPU.
Recently, DG’s Nerdy Story web-site published what is claimed to be a die-shot of AMD Hawaii and after a close observation came to a conclusion that the graphics processor can feature more execution units than are enabled even in case of the flagship Radeon R9 290X. In case the assumptions are correct, then a fully-fledged Hawaii sports 48 compute units, or as many as 3072 stream processors (SPs), 192 TMUs and 64 ROPs. It should be noted that authenticity of the Hawaii die-shot cannot be verified; moreover, certain assumptions and estimations may be incorrect.
Provided that AMD Hawaii does really have 3072 stream processors, 192 texture units and 64 raster operation units, then AMD had one reason to disable some of them in case of enthusiast-class products: to ensure steady supply of Radeon R9 290X even if there are issues on the manufacturing side. It is pretty hard to produce highly-complex chips with all execution units working perfectly and at desired clock-rate. As a result, GPU designers disable certain units to boost the number of chips that hit performance targets and can be shipped to customers.
For example, Nvidia Corp.’s GK110 GPU includes as many as 2880 SPs, 240 TMUs and 48 ROPs. However, only GeForce GTX 780 Ti and Quadro K6000 products use the chips in maximum configuration, whereas other solutions rely on cut-down versions of the GPU.
In theory, AMD eventually could release a new flagship graphics card with fully-fledged Hawaii GPU with 3072 stream processors (SPs), 192 TMUs and 64 ROPs. Such a product would provide ultimate performance in extremely high resolutions, such as 4K (3840*2160), and could be sold with high profit margins. However, at present we do not know whether the company has such plans.
AMD did not comment on the news-story.