OK, I finally got my Mini Ninja & Scythe SFLEX -D fans all in on Tuesday. My system now consists of an AM2 x2 3600+ 65w cpu (no over or underclocking) on an MSI K9AGM2 690g board using x1250 integrated graphics, with a passively cooled Ninja Mini (using arctic silver 3) in a Fusion Black with side front 120mm tri-cool removed & vent blocked by antec plate, and rear 120mm TriCool replaced by a Scythe SFLEX -D model (~1260 RPM max). In other words what MikeC did, except with the Scythe 120mm replacing the TriCool. BIOS set to control CPU fan speed, target 40 degrees C (maybe being too cautious?) minimum 50% rpm. This is a Vista Ultimate box being used as an HTPC (Hauppauge 1600 card, samsung 501lj round it out), running in desktop video resolution of 1920x1200.
I struggled a few minutes to get the Minja mount to stay clipped on, but eventually got it after a little futzing & a bit more swearing. Part of the difficulty might have been that I was mounting it with the board already in the case, which was made worse by also putting the 120mm fan in first (there was not a lot of space between Minja & side fan).
I didn't not stress test it or anything, but I did watch OTA HTPC (720p broadcast) for a couple hours, periodically (usually at commerical breaks -- aka "often") looking at RPMs & temps with speedfan. In other words using it like I typically will be. The cpu temp stayed pretty low, even under 40 C at times (down to 37-38 C) with the fan seemingly always running at minimum of ~630rpm. If it powered much higher than that I never heard it (then again I had TV volume turned up) The ambient temperature was probably about 70 F (not sure what that is in C). The system temperature was ironically higher than the CPU, around 44 C
Maybe I should consider putting in a second SFLEX in the other bay to get the system temperature down, I don't know. But in any case this machine was VERY quiet. You could barely hear it running from even up close, which definitely was NOT the case with the tricools & the stock cooler in there! Very nice, quiet HTPC solution, Scythe Minja/SFLEX + Fusion. I was expecting I might have to replace the PSU fan too, but I think this might be good enough as is.
The most obnoxious thing about it now is the bright blue LED power light