Quote from ArchAngel:
Hyperthreading isn't a dual processor replacement.
Intels' own internal studies show no more than a 10-28% performance boost when running software that's been explicitly written and compiled (using Intel's Fortran compiler) to take advantage of thread-level parallelism and/or vector processing optimizations.
An HT processor only duplicates processor state hardware (e.g., registers, condition states, etc.). The HT logic emulates two processors but with only one set of shared processor resources. Primarily the boost you see (if you see one) comes from parallelizing integer and floating point operations.
So multimedia apps, software that does a lot of mixed integer and floating calcs that can be explicitly parallelized, etc. can be modified to take advantage of this. Adobe supposedly has already done that with Photoshop.
It's not a dual processor and it's way short of dual performance and general mixed workloads will only see boosts at the low end of the scale - but Intel's managed to allow a way to eek out some extra performance from the chip essentially for free.
According to Intel's tests - a single HT processor can perform in the 1.1 to 1.28 times that of an equivalent single non-HT processor and a dual HT processor can perform in the 2.1 to 2.23 times that of an equivalent single non-HT processor.
Target sounds primarily like desktops, especially those using multimedia software.