Most EFTs are rated for 12 volts which is not suitable for a 5 volt system. I'm using this with a small converted 9 to 5 volt power supply and while it comes close to overcharging the power supply (it gets pretty hot) it does the job! but it does the trick. With that in mind, I see no reason to use this for CPU cooling when a 12V port is available, which it most likely is.