If you don't have an SSD, that's a big bottleneck. It can be *that* crazy.
Could be some other factors too. Setup parameters matter. Low latency vs high latency and all that.
Are you performing live through the machines with instrument plugins or running live sound? Or are you recording tracks and mixing?
Apologies if you have gone through everything thoroughly already. I'm sure it's possible to stack up enough CPU hungry virtual instruments to need something cutting edge. Worth taking inventory first though.