starting to make noise? so it didnt before? i suggest re-seating the heatsink with new thermal paste and cleaning the fan. also exhaust fans in the case are a must. doing that is much cheaper than an aftermarket heat sink/fan combo.
Clean the dust out of the heatsink, as the heatsink gets clogged the fan needs to run a lot faster to keep the GPU cool so if it just started making lots of noise its time to clean it out.