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On Sun, 23 Apr 2006, Urs Thuermann wrote:
I'd like to know what is the difference between a system with a dual core CPU compared to two (single core) CPUs. I know dual core means two CPUs on one chip, but is it really two complete CPUs or do they share some component which is used by both CPU cores?
In the case of AMD, the processors, L1 and L2 cache are replicated for a dual-core chip. But the hypertransport to get off-chip is not replicated, nor is the memory controller. So there could be a bottleneck on the dual-core that two single-cores don't have.
But then there is price. The dual-core system will be cheaper than the dual cpu system...
For example HT duplicates only those parts of CPU which hold the state of the program in execution (i.e. program counter, registers, etc.) but they share the execution logic which often leads to performance loss. Is there some performance difference between dual core and two real CPUs, too? I assume the dual cores on one chip must share the bus interface, but since in a multi CPU system only one CPU can access the bus at a time, I think this doesn't make a performance difference, right? Can anybody give some clarifiactions on these issue? urs - : send the line "unsubscribe linux-smp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
- : send the line "unsubscribe linux-smp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html