> 1. The workloads intrinsically lack TLP
>
> 2. The people who coded the current crop of game engines didn't bother to expose TLP
> (probably because current cores are more than fast enough to keep up with gameplay at
> reasonable frame rates. There is consequently little incentive to multi-thread).
>
> I tend to believe (2) more than (1). As others have pointed out, there is known to be a decent amount
> of TLP in physics, AI, etc. You might view Intel's continued investment in SMT for client processors as
> a bet that SW developers will invest in exposing that parallelism (and their continued investment in things
> like TBB, IPP, CPU-side OpenCL runtimes, etc are attempts to make that easier for developers).

I believe that one SMT:s purpose is to get developers work with more threads than cores so that WHEN Intel increases the number of cores users get benefit from it. So SMT should help to move workloads towards more cores before Intel could efficiently have that many cores in mainstream.