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原帖由 potomac 于 2007-3-16 17:16 发表 ![]()
在偶看来:
R600最强就是环行内存控制器。
这个确实够nVIDIA喝一壶的。
ring bus什么时候变得比Crossbar更强了?事实上crossbar的性能更加强大,IBM当初设计Cell的时候,也有几个开发人员力推crossbar,但是后来出于成本的考虑才决定了选择现在的EIB。
参考:http://www.ibm.com/developerworks/power/library/pa-expert9/
Krolak: Well, in the beginning, early in the development process, several people were pushing for a crossbar switch, and the way the bus is architected, you could actually pull out the EIB and put in a crossbar switch if you were willing to devote more silicon space on the chip to wiring. We had to find a balance between connectivity and area, and there just wasn't enough room to put a full crossbar switch in. So we came up with this ring structure which we think is very interesting. It fits within the area constraints and still has very impressive bandwidth |
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