AMD Shangai die size disclosed; Fudzilla hints at 0MiB L3 chip Monday 17th March 2008, 11:00:00 AM, written by Arun
AMD displayed wafers of its 45nm Shanghai chip at CeBit, and Hans de Vries took the opportunity to create a comparison picture between Shanghai and Nehalem (scroll to the middle of page). Surprisingly, their die size is just about identical, so AMD doesn't have the previously expected die size advantage. Or do they? Fudzilla claims that a 0MiB version of Shanghai/Deneb, codenamed Propus, is also coming and that it should be more than 30% smaller than Nehalem.
Shanghai's die size is 243mm² (or 263mm² including test logic) and Nehalem's is 246mm² (or 265mm² including test logic). The number of dies per wafer is barely different if at all thus. Hans' analysis of both die shots seems plausible to us, although as far as we can tell the Nehalem that is pictured there is the 192-bit version aimed at the ultra-high-end and servers, not the 128-bit + PCI Express version.
Interestingly, Nehalem's core size excluding L2 is massively larger than Shanghai's: 24.4mm² versus 15.3mm². Multiple factors are at play there, including Nehalem's support for two threads per core (ala HyperThreading, but it is rumoured to be much more efficient). However, it seems incredibly unlikely that Shanghai will come anywhere near performance leadership against Nehalem given that core size deficit and Intel's leaked performance estimates.
On the other hand, it looks like AMD will have one chip that gives them a cost advantage against Nehalem: Propus. It's a 0MiB L3 version of Shanghai/Deneb according to Fudzilla (whi**as been surprisingly accurate on AMD rumours lately) and should be 30%+ smaller than Nehalem, which matches our own estimate of ~170mm² based on Shanghai's die shot. Even more positive is the fact Fudo claims L3 only improves performance by 5-10% on average and often less in real-world benchmarks. We believe this might be due to the increase in memory latency for cache misses caused by L3, as experienced on Barcelona.
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发表于 2008-8-10 10:37
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