#14 Desactiva el HT y prueba.
Just because you can force it to run on more than 4 threads (which ideally each run on a different physical core) doesn't mean it will actually be faster, hell it might even be slower as you have more threads, which might stall CPU cores needlessly during context switches.
It's like asking 2 people to move a small box from A to B (by constantly having to stop and hand the box over to the other person), sure you can do it, but letting one person do it all is probably faster (even if that means that person runs at a 100% utilization load).
The hyperthreading of the i7 really doesn't help much either, sure it has double the amount of 'threads' (very misleading term IMO which often seems to confuse people) than their i5/i3 counterparts, but those only really help if you have an issue with pipeline saturation, which most games really don't have (especially older ones). Perhaps it actually helps mitigate performance loss from forcing more threads than is ideal (algorithms have sweet spots), but really hyperthreading shouldn't be a significant factor. Most of the performance difference (if not all) between the i7 and i3/i5 can be contributed to the slightly faster single core performance.
There are so many misconceptions and confusions about terminology/architecture/etc it's painful to read these topics over and over again.
No, just because your CPU has 'x threads' doesn't mean you should launch the game with that. These 'CPU threads' have little to no relation to that command line arg and saying you must match them up is complete nonsense.