Well, there you have it. If you are looking for quiet, the ZM80A-HP cannot be beat. However, it does sacrifice a slight bit of performance by not having a fan to keep it cooled. Zalman states in the manual, "You can expect satisfactory cooling performance with the product alone. ..I believe the ZM80A-HP would do extremely well with a fan added to it, as suggested by Zalman. A low noise fan would probably cool the ZM80A-HP well below the TT GF4 cooler, and something like the TT SMART Case Fan II or Vantec Tornado would work much better.