First, I want to say that I am new to computer builds. I have purchased a GeForce GTX 750 Ti to put in my Optiplex 755 SFF. Before people tell me that it can't fit, I am using a PCI-e extender cable to connect them both. The problem is that I was told that I need to connect my GPU to the motherboard. I've looked at many GPU Installation tutorials and no one has had to do anything like that. As you might be able to see, I'm a little bit confused. Do I need a new power supply to attach my GPU to? Do I need to attach this to the motherboard at all?