CPU heat while system is powered off?

[parrotperil]

I haven't had a proper desktop pc in over a decade so please bear with the stupid question but: when I put my computer to sleep or shut it down, all the case fans and the cpu fan (obviously) stop spinning. Is this bad for the cpu?

 

I understand that at idle temps would be less of an issue but say after a long gaming session temps spike at 80-90C, should I keep the system running idle for a bit so it can "cool down" before the fans power off with the rest of the system, or is this totally unnecessary?

[Chionele]

Temps drop pretty much immediately once there's no more load, so you probably even can't shut everything down fast enough for them to not cool down. And as there's practically no load on the CPU when in sleep it's also not going to heat up in any relevant way.

[Kilrah]

Cooling stops, but heat generation stops as well so it's not going to heat up more somehow than what it already was at. 

[NineEyeRon]

The physics of the cooler still work, but at a greatly reduced capacity. Just because the fan stops doesn’t mean metal and air stop doing their stuff.

 

I don’t know the max TDP of a standard air cooler with no fan, it wont be much but its enough to manage a cooling down CPU. 
 

Things might get warmer briefly with no case fans but as nothing is operating this wont get anywhere near the max temps.

[LogicalDrm]

-> Moved to Cooling

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The heat will be stored in metal parts of chassis longer than actual silicon die of CPUs and GPUs cores. Adding to that, damage cause will be from long exposure of very high temps (= over 90C). Heat stored in metal parts of chassis will be hot-to-touch which means they are probably at 40C or so.