everything is simulating/emulating the rather earlier Sunbeamtech Tuniq Tower
Ah. Thanks - I was trying to remember what the original tower cooler was.
Trust, me I have machines with Zalman's I have machines with Nexus and Nexus wins hands down. I used Zalmans for years, but they are leaning more to acceptable noise levels with better performance these days. The Zalman bearings also seem to start getting much noisier after a year or so.
Open air tests like the graph you showed are generally meaningless (which didn't include the Nexus fans anyway) - a lot of fans have low frequency hum that only becomes apparent when the fan is bolted to a heatsink or case. There are other factors you have to look at, especially character of noise - a lower decibel fan may make most of it's noise in higher frequency ranges, which are far more annoying than a louder fan with most of the noise energy in lower ranges.
I also prefer to get my test specs from a site like
http://www.silentpcreview.com/ where noise is the primary concern, than
http://www.xtremesystems.org, where the focus is on performance.
Something that's often missed in these discussions is that almost all "quiet" fan/cooler solutions are a huge improvement over what is supplied as the stock cooler and fans in most machines these days - a Zalman, Vantec, Nexus or even Antec "quiet" solution will make a massive difference anyway - which ones are the quietest is to some degree just nitpicking.
