If you mean software applications by Apps, I don't think it's possible. You acturally have to limit the hardware (electric current) to slow down the fans. You can use a rheostat or a potentometer(sp?) I'm not an expert on this however. Currently I have a Nidec Fan that's controled by variable resistor. In my local computer shop, they sell 92mm nidec thermally controled fans, and I replaced the thermally controled variable resistor with a variable resistor with a dial. If you can find good cheap thermally controled fans, that might be a good way to go.