Basically, in open air, unless you're in a hot desert, I couldn't get it to overheat/throttle. But in an enclosure you need at least a good heatsink with ventilation to allow convection, or failing that, a fan for active airflow.
The CM4 IO Board has a 4-pin fan connector and a PWM chip on board so you can connect standard fans and incorporate them in your designs.
It has to run at 60 degrees Celsius at full speed to maintain longevity, that might not be important for electronics that will have more performant replacements later, but with 1Gflops/watt 32-bit operation the raspberry 4 is peak humanity performance/watt/memory/longevity/simplicity/size/weight/$ (smaller lithography might actually reduce lifespan) so it needs to kept at a cool and silent TDP usage by design, specially since the form-factor has non standard heat-sink attachment.
Fans are not a long term solution to anything and that is what makes the raspberry 4 really valuable; namely it's on the limit of what _can_ be cooled enough passively without adding too much weight/size!
I'm all in on the standard raspberry 4 for server clusters and gaming clients for my 3D MMO that I'm writing from scratch! Sad that the mounting (plastic is not long-term, the SO-DIMM was better in that regard) and form-factor of these are a bit odd, we'll have to wait and see if someone makes boards/heat-sinks for it!
https://youtu.be/vc_Lh_a1BQI?t=463 https://youtu.be/vc_Lh_a1BQI?t=3303
Basically, in open air, unless you're in a hot desert, I couldn't get it to overheat/throttle. But in an enclosure you need at least a good heatsink with ventilation to allow convection, or failing that, a fan for active airflow.
The CM4 IO Board has a 4-pin fan connector and a PWM chip on board so you can connect standard fans and incorporate them in your designs.