Introduction: Use Nvidia GPU Fan As a 4pin PMW Fan(and More)
Just in case some one else wanted to know how to do this.
Step 1: Taking Apart the GPU (EVGA 650 TI Boost)
take out all the screws, if you happen to have a 650 ti boost then i have them highlighted for you.
Step 2: Pint Out and Testing
this tells you what the pins are, for testing i recommend using a 9v battery, if you mess up its low undervolted and low amprege. if you screw up you are much less likely to fry your fan. remember ground is always on the outside and +12v is next to ground. that means if your not sure there only 2 choices.
Step 3: Running As 4pin PMW Fan
this is fairly straight forward, i also have seen if you use it on 3 pin it dose not like to run with the rmp line connected
proof of it working: (8% speed tested minimum 100% maximum)
that's allot of added speed range.
Step 4: Running As Basic 2 Speed Fan
if you can run it up to an 9v battry then you can do this. if you want it to switch between the speeds you can fallow the simple schematic. you could also put a resistor inline with it to drop the speed, or a variable resistor to control he speed. (running like this your maximum speed is lower and your minimum speed is higher so you have less range.) and you could find a dead cdrom drive hard drive to get the connector for you power supply.