It appears to me that the primary difference with AMD's CMT and Intel's Hyperthreading is that AMD is putting more focus on single thread performance and Intel is putting more focus on multi-threading performance. AMD's design appears to have the ability to decode 8 instructions in parallel via 4 fast path and 4 micro-decoders; in sharp contrast with intel's nehalem which only has 3 fast path and 1 micro-decoder


and of course we can always speculate if the SIMD unit can effectively be used as 8 64bit floating point units to execute 8 separate floating point instructions per clock cycle.