I picked up 2 Pi5 cases. One with a fan and an NVME hat - Geekworm Metal Case P579-V2 for Raspberry Pi 5 Support X1000/X1001/X1003/X1004/M901/M300/M400 & Raspberry Pi 5 Active Cooler
and the other an aluminum “brick” - GeeekPi Aluminum Heatsink Case for Raspberry Pi 5, Pi 5 Aluminum Alloy Armor Case, Pi 5 Passive Cooling Case for Raspberry Pi 5 4GB/8GB
Interestingly the “brick” seems to be doing a better job of cooling without any fan noise (maybe losing the possibility of NVMe is not a big deal).
With the “brick” I set the Pi5 to max overclock in webconf and fired up enough voices to get “top” up near 100% also running the Engine UI (which doesn’t seem to actually use so much CPU in Oram) and I couldn’t get the CPU temp above 54deg under about 1/2 hour of load.
Going forward I think I’m going to stick with the passive “brick”.