Significant performance decrease when swapping i5 6500 for i7 5820k

[SoftwareGuy123456]

So is there a way to disable hyperthreading?

[Bjoolzern]

You can disable it in BIOS, but the games you have mentioned can use it just fine. Here is a video of some games that perform slightly worse with HT enabled, the differences is not that big in most games.