ACPI Power states, when do CPU fan, PSU fans turn off/on?

Rodion15

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In which of the ACPI power states on a desktop computer are the CPU/PSU fans on?

I guess in S0 all fans are ON. In what of the other states are fans off?
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Wikipedia: Advanced Configuration and Power Interface:

• G0 (S0): Working. "Awaymode" is a subset of S0, where monitor is off but background tasks are running.
• G1, Sleeping subdivides into the four states S1 through S4:
o S1: All processor caches are flushed, and the CPU(s) stops executing instructions. Power to the CPU(s) and RAM is maintained; devices that do not indicate they must remain on may be powered down.
o S2: CPU powered off. Dirty cache is flushed to RAM.
o S3: Commonly referred to as Standby, Sleep, or Suspend to RAM (STR). RAM remains powered
o S4: Hibernation or Suspend to Disk. All content of main memory is saved to non-volatile memory such as a hard drive, and is powered down.
• G2 (S5), Soft Off: G2/S5 is almost the same as G3 Mechanical Off, except that the PSU still supplies power, at a minimum, to the power button to allow return to S0. A full reboot is required. No previous content is retained. Other components may remain powered so the computer can "wake" on input from the keyboard, clock, modem, LAN, or USB device.
• G3, Mechanical Off: The computer's power has been totally removed via a mechanical switch (as on the rear of a PSU). The power cord can be removed and the system is safe for disassembly (typically, only the real-time clock continues to run - using its own small battery).
 
When temperatures require them to be on.

The PSU controls its own fan.

The motherboard BIOS is normally what controls the CPU cooling fan. The default is to run fans until temperatures have come down to a safe point, and the CPU is in a deep sleep. At that level, the CPU will not produce enough heat to need active cooling. As soon as the CPU comes out of deep sleep mode, the fan will power up, and active temperature monitoring will resume.
 

Rodion15

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Thanks for your answer, it's good to know that. But, could you be a bit more specific? What's the typical behaviour of PSU, CPU and case fans in each of the sleep states? Do you mean that in S1 state (which is the most awake of the sleep states) all fans will turn off if the temperature goes down to a low enough temperature?
I know that in S3 and S4 fans always turn off.
Thank you