[jnd426]

Might or might not be a silly question but like the title says can I use a controller on my gpu fan?

 

[Mr.Taquito]

im not exactly sure on that... but i doubt it.
just use tools like Rivatuner to control it.

 

[Puscifer]

Technically you could but you would probably be better off just using rivatuner. Most GPU fans use a 3 or 4 pin mobo connector that connects to the card, so you could unplug it from the card and run it through a fan controller I suppose. Just using rivatuner to control the fan speed is about 100x easier though.