Optane isn't going to boost the performance of a native SSD you already have.  If the CPU is maxed out, see what's consuming its time (open the task manager) and disable the service(s) you don't need -- these may include many of the Dell support assist services, and if you have it installed, dispatching McAfee in favor of Windows own security software will likely help quite a bit.  
Hey guys, first off I would really appreciate your help. I'm wondering, if I can upgrade the CPU somehow. I've already upgraded the RAM and it really works nice, but CPU usage is always above 80%, mostly at 94% avg. This is just insane, if you think about spending almost $1.500 for a Laptop. Due to my job I am using several clients at the same time connected to 2 external screens, seems like the 7786 just can't handle it. I've also disconnected the monitors, but the CPU usage doesn't change. Like I said I would really appreciate some help. Thanks in advance.
Inspiron 7786 - Upgrade CPU