Don't mean to jump into an old thread, but the EKWB D5 PWM pump I have been using works great. It is virtually silent at 100% (I have to take the tempered glass off to hear it).
It works so good I just bought a used pump and res combo off of ebay to use on another side project.
One of the other poster's stated correctly that you need to properly isolate the pump with vibration dampeners (like foam pads).
My pump is isolated from the case with rubber pads on the Pump Phanteks Bracket. Then the pump itself is mounted in a anti-vibration rubber ring on the EKWB pump bracket (which is mounted to the Phanteks Pump bracket).
Build: Z390 ACE
Core i9-9900K OC 5 GHz, MSI Z390 ACE Mobo, AMD Radeon VII GPU OC 2K MHz
Corsair Vengeance RGB 32GB 3200 RAM, Phanteks Enthoo Pro M SE.
EKWB Z390 ACE Monoblock, Bykski Radeon VII GPU w/b, 2x EKWB 140 Revo D5 Pump & Res.
Aquacomputer Aquaero 6 LT USB Fan-Controller, Quadro, Vision Touch and 'High Flow' Sensor.
(2x) HWL Black Ice Nemesis 280 GTS XFLOW and (1x) Alphacool XT45 X-Flow 280 radiators.