PC Set up and specs

Hello!

I recently had somebody build a custom PC to use with Premiere. I'm mainly a Mac user so I totally relied on their advice. Here is the system they built for me:

• Intel Core i5 8400 CPU @ 2.8GHz 
• 16GB RAM
• 64 bit based processor

They said that the comp was built using the reccomended spec as stated on Adobes website.

When editing footage from a Canon 80D and Sony A7III playback sometimes stutters and other times it plays back with no sound even though it is there and not muted.

I sometimes feel that my MacBook Air (1.6 GHz Intel Core i5 with 8GB RAM) performs better!

Before I go back to the computer company can anybody give me some advice on what to say / ask for please?

Thank you,