is it possible to hook a Rheostat from the 12v gpo's to a fan. i know these gpo's are great for fans, but i want to run the fan at a lower voltage using a rheostat. Will i encounter any problems?

nevermind, i found the answer in another thread

how many fans or whatever 12v devices can i hook up to the lcd. I see it has 8 gpo's but i read somewhere that it can only handle 4 12v devices hooked up? Is this true.