DC or DCV = Direct Current as opposed to PWM
Was a time when I wanted all my fans to be PWM, but I don't anymore.
1. PWM's advantage was excellent low speed control. The constant 12V allowed fans to start up with enough oomph to overcome inertia and get the blades moving. DCV OTOH, when low speeds were called for could not overcome that inertia. Downside to PWM ... a) cost b) low speed hum / ticking noises and some brands (particularly Corsair, ya couldn't gang many on a single channel.
2. These days, MoBos utilities have gotten sophisticated enough to start up the DCV fans with a bit more oomph and thaen trail back once blades are moving. You can even call for fands to stoip below a certain rpm and ramp speeds up and down. The later is useful for water cooled systems subject to varying laods which eliminates the whiring sound accompanying rapid load chnages and all lets the fans seep running at higher speeds sor a time to remove hear from coolant. Also, DCV fan design has improved such that they now perform at speeds comparable to PWM.
3. We also have fan control PCBs which will take a PWM signal and control say (6) DCV fans on a single channel with no auxillary power cable.
As for fans ... for the most part, there's not much difference between fans ... that's for the
**MOST** part.
http://www.overclockersclub.com/reviews/phenteks_f140/3.htm
Here we see that replacing the venerable NF-A15's for example on a Noctua Cooler with Phantels fans drops CPU temps by about 3C ... however, the Noctua fans are 1500 rpm, and the tested Phanteks fans are only 1200. Running that both at 1200 rpm and the Phanteks fans drop CPU temps by 6C. That's a pretty astounding change.
4. Martin (of martinsliquidlab) isn't around to do the massive fan comparisons he did back in the day and much of the data is now questionable as the days of hi fpi radiators are well in the past and high SP is not needed any more. The last decent size roundup i saw was here:
http://www.silentpcreview.com/article1345-page7.html
... with the top ten at the time being 1) Phanteks PH-F140HP/TS, 2) Noctua NF-A14 FLX, 3) Noctua NF-A15 PWM, Noiseblocker B12-2, Noctua NF-P14 FLX, Scythe Gentle Typhoon 120-12. Noiseblocker M12-S1, Corsair AF120 Quiet, Corsair AF120 Performance, Thermalright TR-TY150
Since then two fans have impressed me, ... the Silent Wings 3 and the as yet unreleased Noctua strengthened blade designs w/ minimal blade clearance. That leaves the Wings to consider and from what I have see I think they are as good or perhaps even better than the Phanteks ... but at more than twice the price, ... I have 16 fans in my box (10 rad / 6 case), I'm not gonna invest in a swap. I usually grab a dozen PH-F140SPs at a time ... they are bout $10 each every cupla weeks on newegg... about $8.50 for the 120mm. The Wings on the other hand run about twice that for the 140s and 2.5 times for the 120's. Always looking to learn about new stuff, so if ya see anything, please list.
