FF15 and GTA5 come to mind.
FF15 never pegged my cpu cores at 100% on my quad core processor, but stutters were caused by saturation, people with 4770k's reported the same issues, htt would potentially help on FF15 but nowhere near the impact of that AC game.
GTA5 when you crank up the advanced graphics settings, its hard on the CPU in city areas, again tho like FF15 it doesnt stay at 100% pegged, but it is capable of maxing out all cpu cores, so that would be another candidate for HTT to help. I remember someone doing a HTT test on GTA5 once and if I remember right there was an improvement, not large but it was measurable.
So I will back of a bit on this HTT performance issue, in "some" games it can have a benefit, and one confirmed game it has a moderate benefit providing you playing at really high framerates.
I await now to see what the OP says after he fits his new cpu, if he feels he has an improvement.