Not a fan of using a closed loop cooler to 'liquid cool' a GPU considering that most of the units used for this are a single 120mm radiator and a GPU often has a much higher TDP than the CPUs they were designed to cool. If you want to 'say that you liquid cool' but don't really care about cooling delta, sure, use one. For example, your 75C would be considered very high on a watercooling loop for GPU temps. For reference, my GTX 770 never gets over 45C at full load.