Molex Fans rpm?

So if you hook up a molex fan directly to the molex adapter will they run at full speed or not? My power supply is a corsair cx500 and yeah bought some cheap ass fans on ebay.

Yes.

I only use molex to test fans. Jet engine mode: ENGAGED

If you want a quiet PC that's not the best idea because they will run at full speed. If it's cheap fans from ebay they will probably be loud as hell! Plug them into the fan connectors on your motherboard instead, if you have any.

If the situation is dire enough and you don't have 3or4 pin connectors you could(with a little tech saavy) make a controller with less then $10 of parts from radio shack. You'll have to gut some miles adapters or hardwire your fans into it though. 

yeah they are not that loud to me. My Cooler Master Hyper 212 Evo fan is even more audible since its running at 100%  :p

you need fan reducer 3/4 pin adaptors like the Noctua low-noise adaptors. Or you can solder your own resistor on them if you know how.