Finished cutting out the last perf hole.
Fired her up and read my idle temps.
Before perf hole cut out at idle
CPU - 36C
MB - 35C
After perf hole cut out at idle
CPU - 34C
MB - 30C
How does it sound?
I only had one 80mm fan on the back of my tower that was also blocked by perforated metal and I cut out the hole to fit a 120mm fan. I have an 80mm on the side too. I replaced the ones that came with the tower with fans that use a fluid dynamic bearing design. (guess who pointed me to those)
Boy, what a difference. Not only did the temps drop but tower was much quieter.