I have a project that has 5 cameras. All footage is 1080p 29.97. Each clip plays fine until I go into MultiCam mode and then it plays back so slow and choppy I can't edit it. I was using linked clips at first the I transcoded averything to AVC-Intra 100. It took 14 hours. Made a new Multicam Group and to my dissapointment the same thing. Any suggestions.

Yes, Employ an online to offline workflow. Here's a tutorial: https://youtu.be/PKaK397eVLI

Also, what are the specs of the mac and what is the Media Composer version?

AVC intra isn't the best codec to edit with. In short. AVC intra is a Long-GOP codec. DNxHR LB for example is an intraframe codec. We need to work with Intraframe codecs during editorial. 

I'm more than certain that the wrong choice of codec is causing the sluggish behaviour in this particular instance.