What is the difference between a CPU fan and a case fan?

Question

I know very little about fans except that I have an Arctic Cooler 11 LP in my current system to cool my CPU, and that my hard drive temperatures tell me I need another one at the back of my case's grill as an exhaust. As a result, I'm feeling overwhelmed at the many options out there and unsure exactly what I need to be buying.

The problem is that while I see a majority of fans on Amazon claiming to be CPU fans, I don't see many at all that are termed case fans.

Is this a matter of terminology? Are CPU and case fans essentially the same thing? Would I in theory be able to buy another Arctic Freezer 11 LP, separate the fan from the heatsink and attach it to the back grill of my case as an exhaust?

Solution

What is a CPU fan?

• A CPU fan is a fan that mounts on top of your CPU. A CPU fan, is also known as a CPU cooler, or heatsink. The CPU cooler will have a base that sits on top of your CPU, which is normally made out of copper, aluminium, or a combination of both. The base will have heat pipes that connect to fins, where the fan sits. The heat is transferred from the heat pipes, to the fins of the cooler. The fan on the cooler then pulls the heat away from the fins and into the air to be pulled out by the case fans.

What is a case fan?

• A case fan is simply a fan that is mounted on the inside of your case. Depending on the location where it is mounted, it's referred to as an intake, or an outtake (exhaust) fan. An intake fan is used to pull cooler air into the case from the outside environment. The outtake or exhaust fan is used to pull the warm air from inside of the case and blow it outside of the case.

Could you take the fan off of a different CPU cooler and use it as an exhaust fan?

• While you could take the fan from another CPU cooler, it would be much cheaper to just buy a case fan. A 120mm fan is the standard and should work for your case.

Comments

[Kamil Maciorowski]

Probably 120 mm Standard Case Fan is the right phrase to begin with.

[ivanivan]

Been a long time since I've built a system but IIRC most CPU fans will have brackets or other methods of attaching to a heat sink, whereas a case fan will simply have the 4 corner mounts to attach to standard size openings.

[Hashim Aziz]

@KamilMaciorowski My case has a 9CM grill at the back of the case, so seems to require a 9CM fan.

[Hashim Aziz]

@ivanivan Does this mean that the two aren't interchangeable? That CPU fans and case fans are actually different things?

[ivanivan]

You can probably make it work. I question if it is worth it... Most CPU fans are more expensive than case fans, because of those connection issues, etc. Also, an appropriately sized fan housing will make it fit your case properly, which will help with keeping air flowing the way it was designed. Use the right part for the job - get a case fan for your case.

[Hashim Aziz]

@ivanivan I was having a problem finding many fans at all that are 9cm apart from a handful. Maybe this is an Amazon bug relating to Black Friday, as doing the same searches on NewEgg returns plenty more results.

[Hashim Aziz]

@ivanivan Although even NewEgg is relatively limited when I start filtering by noise levels. Maybe 9cm is a particularly unpopular size?

[Jamie Hanrahan]

That size is more commonly stated as 92mm. Look for that. And try specialty vendors like xoxide.com or frozencpu.com . (no affiliation except as an occasional, but satisfied, customer of both)

[Giacomo1968]

A CPU fan goes onto the heatsink of the CPU and a case fan just vents the case.

[Hashim Aziz]

@JamieHanrahan Thanks so much! I didn't realise these sizes were more or less standardised, searching for 92mm instead of 90mm or 9cm did exactly the trick.