120mm vs 140mm

[Brian@NCIX]

Hi guys, new here, anyways i was arguing with someone over the sizes of fans 120mm vs 140mm's.

My argument was that 140MM is starting to become the new norm because they have the ability to push more air when needed and are quieter when doing so.

While he argues that 120MM are just made better and can push more air because 120MM = optimum size for fans.

Can I get some opinions or facts on whats better? I know through knowledge, assembly & reviews that 140MM are indeed better if given the same series of fans, same RPM, same construction and same bearings.

[maverick_brent]

my understanding is that a larger fan takes less rpm to move the same air, lower rpm should mean lower noise, thus giving a better air/noise ratio...

[ilya]

While it's true that 140mm fans typically give better airflow/noise ratios than 120mm fans, those aren't the only two factors in deciding the optimum fan for the application. Airflow means nothing if the application requires static pressure or simply doesn't have the clearance for 140mm.

Modern computer fans typically come in 25mm thickness, with exotic ones coming in other thickness like 12mm and 38mm, which doesn't bode well for larger fans in terms of static pressure. There are very few 140mm fans out there that can match the static pressure of 120mm fans designed for high static applications.

There's also the size limitation of your typical rear case fan. In order to have room for a 140mm fan next to your i/o shield, you'd need a significantly wider case. Add the fact that the demand for cable room behind the motherboard tray is increasing for DIYers and you simply don't have any room for 140mm fans without getting well over 200mm in case width.

We might be seeing a large shift to 140mm fans in terms of exhaust for larger cases, but 120mm fans are going to stick around for quite some time, for reasons similar to why 80mm fans have stuck around so long. It's not a case of what fan is better, but what fan you need for a specific application.

[Stock]

If the designs are identical, then yes the larger the better. I'm not really sure why he said a 120mm fan is the best? Maybe he meant that it's a more common size for cpu coolers and case fans?

[JMCD]

I find 120mm's are best, simply because there are so many choices because it is the most common fan size. 140s are great, but I believe the best 120s are just optimized better. I would opt for 140s cause I like it quiet though.

[_dangtx_]

the bigger the fan that you can fit, the slower, the less noise, the better.

but not necessarily on your heatsink, unless its made to run off any air movement :)


how about this puppy?

::: Zalman, leading the world of Quiet Computing Solutions :::

[JMCD]

Those are great options. I have a 92mm that fits 80mm holes, kinda the best of both worlds. Biggest I've used was for a friend's build, 36cm fan lol

[Eluder]

I use Noctua in my system, their NF-P14 FLX. 140mm, but with 120 mm mounting options.

[Soultribunal]

140mm Fans will generally speaking push more air for less RPM (they have a larger blade, therefore more air movement) so ideally they do what a 120mm can do except quieter.

There are some (Not many) 140mm fans that are more optimized for Rad/HS duty but being so few and far between 120mm fans will still reign supreme in that field for the time being. Namely because they have been a standard for much longer than the 140's.

That being said, in the future as case fans keep increasing in size I am sure we will see more and more offerings for 140's that will far surpass what the 120's can do at this point.

Back to the original question, both of you are right in essence

ST

[enaberif]

140mm fans usually have a larger dead spot than a 120mm too which can make a 120mm fan ideal for better environments.