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I was curious as to whether I can make the fans run while the GPU,CPU, and hard disks are powered down. I want to do this to help cool down quickly without the components generating extra heat. is it possible to do this and if so how may it be done?

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No this won't be possible. Determine why your system is generating so much heat. I assume shorting pins isn't a solution – Ramhound Aug 27 '13 at 1:39
You could possibly use an external fan - maybe like those USB powered ones to get air through the system initially. Back in the day, I used a mains powered box fan to rapidly get an overheating system cool – Journeyman Geek Aug 27 '13 at 6:05
@ZCoder If your computer whirs the fan on maximum at startup, you can sometimes keep the fan on by bringing the BIOS settings up. That way, the OS doesn't load and the fan isn't slowed / disabled, as well as it not running the CPU high (and possibly not the hard drive at all!). Not exactly what you asked, but it might be what you meant. Please reply if this helps. – wizzwizz4 Jan 11 at 18:57

For what you want to do your only options are motherboard specific features. You will need to check the documentation of your motherboard or of the board you want to buy.

If you want the power supply to supply power to fans (or more common use for this trick, liquid cooling pumps) without powering the motherboard you can disconnect the power cables to the motherboard and use a wire to connect pin 14 (green) and any ground pin (black) on the ATX cable. This will turn thee power supply on and any attached fans or pumps with it.

Often this is done to prime liquid cooling systems when you are not sure yet if there are any leaks.

Pin out available here

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I suppose, though it would be more of a hassle to disconnect the 24 volt every time unless I use another power supply. I do have one, but is there a risk of fire from connecting these pins in this way? – ZCoder Aug 26 '13 at 22:59
If done correctly no, but you could short the wrong pin and depending on the power supply could cause anything from nothing at all happening to a fire in the power supply. – Scott Chamberlain Aug 26 '13 at 23:02
oh wow. I really can't deal with an electrical fire right now :s – ZCoder Aug 26 '13 at 23:05

Without some custom hardware hacking, no. When the system is in standby, only the 5 volt standby rail has power. The fans are driven via the 12v rail when the motherboard is fully powered. Of course, a modern CPU uses extremely little power when it is idle. Unfortunately, GPUs, at least from ATI, still burn power like it's going out of style when idle. You can put the hard drive into standby mode while the system is on to keep it from generating heat. In Linux this can be done with the hdparm -y command.

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The CPU and GPU generate the most heat turning off the hdd. Not running a program that ramps up these devices is the aolution – Ramhound Aug 27 '13 at 1:42

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