I'm looking to watercool my 4790k, I want to get corsair fans with the red ring but I am not sure weather to get SP or AF fans, I understand that AF are better for open air spots, like exhaust on the front or back, but what about on a radiator? Also, should I go with high performance or low noise, couldnt I just lower the RPM on the high performance one but have extra speed if I ever needed it? Thank you in advance!