iMac 4K (2017) lags after upgrade

[szw75]

So recently I upgraded my iMac 4K (2017) from i5 7400 to i7-7700K (delidded), also went from 8GB to 32GB of RAM. I noticed that everytime I export audio in DAW, the temps are growing up to ~ 80°C and system is lagging very much. I can't even move the cursor. What's even more the power supply is producing weird buzzing sound. Well I am considering downgrading to 7400. Are those temps normal? How can I prevent my computer from lagging?

 

[mreg376]

The temps may be normal. But the lagging isn't. The i7 has plenty of horsepower even at its max temp of 100C.

 

[MandiMac]

Could it be that the PSU is not ready for the 7700K?