This is my second try building a quiet PC. Last time was many years ago. (2001)
The setup is an intel NUC 11, Tiger Canyon i5@2.4Ghz, with 32GB ram and an NVME drive
Before moving into this big block of aluminium, the CPUs ran at a bit over 70c at full load.
After moving to 100% passive cooling, they stabilize at around 70c as well. Case gets warm, so clearly working.
