I know that after a hour of two of stress testing an aio it would be the same as an air cooler.
So what should I get a clc 120 or h90?
AIO liquid coolers are not automagically quieter that the good air coolers. More moving parts.
I went from a CM 212 Plus to a Cryorig A80 280mm liquid cooler.
Much better temps, but it is indeed louder. It's not bad, but it is noticeable.
And if I do get a 240mm should I get Vega clc 240mm or h115i?
As others have said you would be better off with AIR cooling than a H90 if your OCing.
I have the H115i and changed the SP fans for ML series and they are very quiet. Not so when you use Corsair Link to crank your fans if needed. If you intend an OC and a H115i will fit your case then I recommend it.