The review on OC.net isn't ideal because these fans are strictly single purpose push fans. As soon as there is something disturbing airflow less than 1cm in front of the fan, like a fan grate, a dust filter or a heatsink they can drone. If used in a push configuration I found you can run them ~300RPM faster than other fans at the same noise level.
This information is from the German forum hardwareluxx
where the manufacturer answers user questions.
How exactly is that feasible, though? I can't put it as a front intake because the dust filters/hdds will cause it to drone, and I can't put it as a cpu fan because the heatsink will cause it to drone. Also, I don't really want to have an intake fan without a dust filter because I'm lazy and I don't want to be cleaning dust off the inside of my computer every 2nd week. Any other places these can be used?
If you want to strictly avoid using them in a pull configuration, you can use them as CPU push or as case exhaust. Or, like me, as an intake fan that is somewhat at a distance from the intake filter. When Koldun wrote "in front of the fan" he meant it in terms of airflow, i.e., something blocking the intake side.UPDATE:
So I installed Windows 7 and used Fan Xpert 2 to get fine control. I also tested the pull fan specifically to see if I could isolate the drone noise. Here are my results.
Here we come to the fly in the ointment:
- Bottom intake B12-PS (angled, somewhat at a distance from a dust filter):
RPM: 382-1387. Top speed is a bit low for some reason.
Noise: somewhat higher pitched than the others. Still OK. No drone.
- Bottom intake / half-push M12-PS (angled, somewhat at a distance from a dust filter, aimed at CPU heatsink):
Noise: an extremely pleasant low whoosh. No issues whatsoever.
- Top B12-PS exhaust fan (with wire grill on exhaust side)
RPM: 483-1581 (note: high min RPM compared to spec 400 *may* be due to airflow from other fans, or something to do with the header; I didn't test this).
Noise: quiet even at relatively high RPMs. Agreeable quality, though higher pitched than M12-PS. Subtle motor tick at extremely close distances.
- Top GPU M8-P exhaust fan (very steeply angled, aimed practically at a side panel - this is an odd bracket)
Noise: very quiet up to about 1250 RPM. At high RPM, the noise becomes fluttery and uneven, with a bit of a windy quality. However, this fan is mounted in an very unusually-oriented bracket right next to a panel and may or may not be doing anything useful, so this isn't a fair test.
- CPU pull-side B12-PS fan.
RPM: ~400 to ~1500 (I tested it, but stupidly forgot to mark it down; however, it definitely got down to something close to the official spec).
Noise: ouch. I can now confirm, quite definitely, that these fans do NOT work well as pull fans. At anything above 550 RPM or so, a weird drone noise was heard, faint at first but becoming quite obvious by 900 RPM. It sounds almost exactly like whistling and humming at the same time (not my video). It isn't just an interference at specific RPMs, it is constant and scales dramatically with RPM to the point of being quite blatant and high-pitched at max RPMs.
Apart from that issue and the cost issue, this fan is great. I am very happy with the performance and the super-low RPM noise (or lack thereof), as well as the modular cables, open corners, integrated cushioning, mount design, wide PWM range, and horizontal usage rating. But I admit the M12-PS is a noticeably better fan for sound quality
, even if the B12-PS is more than competitive on a sound level
(per RPM) front.
That pull drone, however, is a real downer. It also puts me in a bit of a quandary; my heatsink fan clips require open corners, which my M12-PS doesn't have. I actually have a set of fan shrouds built for this heatsink, which could mount the M12-PS (letting me swap it with the B12-PS), but the problem is the M8-P in the GPU exhaust bracket practically doesn't fit already, it's so smashed up against the side of the heatsink - it definitely won't fit with the shroud on. I could remove it, since it arguably isn't helping much anyway, except with my non-reference graphics card cooler design, I would rather keep it in if possible. I also bought the dang thing and bent a fan clip to fit it in there, so I'm feeling stubborn about it.
Probably at some point I will remove it though, and swap the M12-BS and B12-PS positions.