Unless it's a custom water loop and gpu is water cooled with a 360-480mm radiator with the fans turned down low, relying on air cooling the gpu will always make some noise under load. Aio coolers aren't known for being silent, larger air coolers can cool just as well and tend to be a lot quieter. Coolers like the be quiet dark rock pro3, noctua nh-d14, phanteks 140mm coolers, etc.
I'm not as familiar with that case but newegg says it supports up to 10 fans? You have all 10 fans in it? More fans don't always make for a quieter case, fewer strategically placed quality fans with fan speed control will provide ample airflow and low noise. Also noted that the c70 case mostly supports 120mm fans, typically 140mm fans will move the same amount of air at lower noise levels. Would require a case that supports 140mm fans.
My current case is an enthoo pro, not really built for sound control. Open bottom, front, top and mostly vented/open back with a window panel (supposedly makes a case louder). A 4690k oc'd to 4.6ghz and an hd7850 gpu (aka noisy under load, sounds like a vacuum). Only 4 case fans, a 200mm front intake, 140mm rear exhaust and 2 140's on top exhausting, all used with a fan controller. Hardly makes a sound, the 2 loudest things are hdd seeks and the gpu when playing a game. Making a quiet pc doesn't have to mean a ton of fans even when the case isn't designed for it.
Adding soundproofing type eggcrate foam or similar may help some but may also change internal airflow some. Two types of dampening, a more solid/dense foam stuck directly to metal interior of the case to 'deaden' rattles/vibrations, the wavy open cell 'fluffier' type foam for controlling higher pitched things like whining sounds, air noise/turbulence. More or less the cherry on top to an already quiet system, may not turn a noisy system 'quiet'. Sound will still escape from front/rear fan openings where air is moving through.