SPCR

Has anyone used the super flower PSU? it has 140mm fan? would the larger fan help to reduce noise level compare to 120mm fan? This is the link to superflower:

http://www.super-flower.com.tw/english/14cmfan-psu.htm

They have come up on these forums before (check search results) but I don't think anyone has tested them extensively.

Just one point to make - bigger is not necessarily better.

If you have two fans of equal quality and different size running at the same rpm, the smaller one will be quieter. There is a minimum speed at which fans can run decently and reliably, and with it there is a kind of minimum performance they will offer and noise level. Now it may be in your application that you need as much airflow as possible, and thus the largest fan you can fit will give you the quietest sound possible. However, in most applications there is a sweet spot where there is "enough" airflow, and the least noise produced for that airflow will be a different size fan - not always larger. Take for example the seasonic S12 PSU which uses a 120mm fan and the Antec Neo HE 430 which uses an 80mm fan. The S12 has been king of quiet PSUs for some time, yet the HE 430 is equal noise and slightly quieter at low to middle loads: http://www.silentpcreview.com/article273-page5.html. Now given this fact, I doubt that a 140mm fan in a PSU will be quieter since the sweet spot is around 80-120mm of airflow.

If you had a lot of room between your PSU and heatsink I think you could use a 14cm fan PSU to get a lot of airflow by reducing the backpressure on it, ie by removing the grill and mounting the fan on the outside of the PSU case.

I have that PSU and I am very satisfied with it. My rig is relatively low powered, so I don't know whether the PSU fan would ramp up under a "mid-range" load of 150 watts or so. I have an XP-M 2600 CPU and a Radeon 9250 video card. The SuperFlower power supply is essentially silent at this load.