Well the two Aio's i have are pretty quite no louder than when i was running custom loop
Even with all fans at their slowest still cant hear them
I assume you mean you can't hear pumps with fans at idle? How close to pump is your ear? At 3+ feet from case many CLC pumps are inaudible or barely audible as long as no air is moving through system.
My be quiet! Silent Loop is quiet, inaudible unless ear is like 6" away. But it's an AIO so not the same as CLCs which are a sub-group of AIOs. AIOs not CLCs are better quality, but still not near as good as mid-level custom loop components.
Most CLCs are made by Asetek who now say they are up to 4th generation of pumps, but as they don't publish any pump performance specs and cold plates all look the same,what if any performance differences is there between older and newer gens? Are there any real differences or are the changes mostly cosmetic?
These pumps' flowrates are very low, like about as fast as a health adult can urinate. And the total volume of coolant is amazingly small, like half a cup.
I've tried to find more info about CLC pumps and there's not much available.
Below are some links to what I have found about different generations by reviewers who have disassembled Asetek's different Gen pumps and other CLC pumps too:
https://www.gamersnexus.net/guides/2539-taking-apart-an-evga-hybrid-liquid-cooler
https://vicyofreetime.wordpress.com/2015/09/21/whats-inside-the-asetek-4th-gen-aio-block/
https://www.chiploco.com/asetek-releases-4th-generation-of-patent-all-in-one-liquid-coolers-18228/
Quick search finds no disassembled Asetek Gen 5, but did find some talk of Gen 6 which I know n
There is also a rectangular based pump on Hydro Series H5
http://www.frostytech.com/permalink.cfm?NewsID=121667
Here's link to 2013 roundup of several pumps. While most are Asetek some are other OEM but almost identical design.
https://www.legitreviews.com/120mm-water-cooler-round-up-part-2-looking-inside_129601/8
I'm hoping AsetekDennis can convince Asetek to publish their pump performance specs.