> The way I heard an Intel engineer explain it, unless the code is highly optimized, a > single thread running on a processor can leave it idle for a significant number of > clock cycles. Hyperthreading allows you to reclaim those cycles and utilize the > processor more efficiently. So it depends somewhat on what you are doing, but there > is definitely more to hyperthreading than just marketing BS.
HT wasn't great when first introduced on the P4 (although it did noticably smooth out animations in the Windows and Linux GUIs) since the P4 never had a lot of power to begin with. But on the Core and Atom chips there's definitely something to it. It's not like Intel marketing invented SMT (the correct term) - IBM was working on it in the 60s.
Also, I think it's entirely possible that some workloads do win on the Atom without cheating. Processor design is a giant maze of trade-offs, and generally neither Intel nor AMD are making exactly the right set for MAME.
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