Case Fan CFMs

[Teny]

Question about fan CFMs. How much is a difference is 70 CFM compared to 45 CFM?
Like whats the difference in temps when using the fans for side intake. For example, placing them on the side of the case and cooling either the GPU or CPU. Would it be more of the line like 1c-2c or more of 5c, etc.
Thanks in advance.

 

[sniperviper21]

More Cubic Feet a Minute of air moved equals more heat that can be removed. but also more air.

High CFM fans are usually for exhaust.

 

[Teny]

So then how much of an impact will it make when using it as a intake?

 

[sniperviper21]

depends on your case, set up, ect.

better out then in i say.

 

[detox1]

as sniper says, plus, it's better to have negative pressure in the case. as to have cool air being sucked into the case. but you don't want to have all exhaust fans thou, you want just a little bit of negative pressure.

 

[Teny]

Alright. I was just asking to see if I should use a certain fan I have in hand right now or not, or I should buy another fan.

This is what I was planning to do. I found this picture on Google, and thought it was a nice idea.

However, I recently bought a Scythe SlipStream Slim (120x120x12, 45 CFM, 37 dba). I originally planned on using it for my Hyper 212+ heatsink since a regular size blocks one of my ram slots. However, it didn't perform as well so I took it out. I figured out a way to mount the stock Hyper 212 fan back on, and now it works. However, now I have a Scythe SlipStream Slim that is just sitting there. So I am debating if I should use the Scythe to put it where the Google picture has it, or if I should buy a regular fan that has higher CFM. Noise doesnt matter as I will be using a fan controller.

If the temps where to change about ~1c-2c difference between a 70 CFM fan and a 45 CFM fan cooling the graphics card, then I will just use the Scythe. But if its more along the lines of ~5c-7c, then I will consider it.

 

[Cabbs]

The difference between 45 and 70 CFM in a fan placed like in the picture won't have a big effect on temperatures. However, the difference between having a fan and no fan in this situation should make quite a difference. Setups that have the best airflow over components get the best results.

Your Scythe Slipstream isn't ideal for heatsinks, which is why it didn't perform well.. It's design leads it to perform poorly when static pressure comes into play (like on a heatsink or radiator). This is why 38mm fans exist, but 25mm thick fans perform well enough for most people.

 

[sniperviper21]

look at nactua heat sinks perhaps ?

but i have that pictured setup in my 1200 and it lowered my temps.10c

 

[setishock]

In that setup all that's going on is recirculating the already warm air toward the cards. If there was a snorkel going to the outside then it might help some. An internal recirculating fan is really a waste of the power to spin it.
Also in the shot the wires are blocking the airflow between the cards and are dangerously close to the fan blades.

 

[Teny]

I'll be switching my case to the Corsair Obsidian 650D, so there will be a 200mm intake fan in the front that will blow directly to the graphics card. However, when I found that picture, it was on a forum where the guy did the same thing with his 650D, and noticed his temps dropped ~10c (similar results to sniperviper21 it seems).
I won't be putting the fan that close to the wires., but I was just curious if the difference between the Scythe and a regular 120mm fan would be worth the investment. But since Cabbs said that there won't be much of a difference, then I will be using the Scythe fan.