Salutations, mortals, gamers, nerds, or people that are reading this for some reason. Today I will tell you about some tests I did over an interesting thought I had when I was randomly staring at my computer.
I am lucky enough to have a case with a glass panel. This means that I can see its internals while simply twisting my sternocleidomastoids. (Neck muscles which turn your head. I know I am so smart). While I was doing something random, (waiting for a Titanfall 2 match and praying to the gods that it is not attrition, thinking about how a 4k monitor would look) I just glanced into my case and realized that my cpu cooler, which is a Scythe Fuma 2, did not have a third fan installed above my VRMs near the back of the case, however my rear exhaust fan (which is set to max RPM since my other exhaust fan doesn’t work and hasn’t spun since day one, and is still in my case because I am lazy) was so close to the back of my dual tower heatsink that I started to think that maybe that rear exhaust fan had a similar effect to a third fan on my heatsink. I was actually quite curious about this, so I decided that I would test the CPU temps in Apex Legends with the following configurations:
- Having no exhaust fans and no third heatsink fans
- Having one exhaust fan like my current setup (testing two different types of fans in this position)
- Having a third fan on the heatsink and no exhaust fan
and,
- Having both a third fan on the heatsink and an exhaust fan.
How I made sure the tests were fair
Just to clarify, there are several different types of fans, the main two being static pressure optimized fans and airflow optimized fans, and if you are unfamiliar with the difference, static pressure fans are meant to primarily drive air hard. Like not simply move it, but do so with a lot of force. The amount of air moved is less important than the momentum at which it is moved at for these types of fans, and they are primarily used in applications where air must be moved through tight, cluttered or filtered spaces such as with fin arrays in heatsinks like mine or radiators for water cooling. Then there are airflow fans, which are primarily used when you simply want to move air in or away without too much consideration for where exactly it goes afterward, which is perfect for a case fan. These are optimized to move as much air as possible rather than to increase the pressure of air that is moved. It is more important for a case fan to move a lot of air than it is for one to move air with a lot of pressure, unlike a fan on a radiator. Most case fans, for this reason, are airflow optimized, and most fans on radiators and heat sinks are static pressure optimized. The reason I am explaining this is because you might be confused as to how I am properly going to test this, since if I simply plop my case fan on the back of my heatsink it would be naturally more effective on the edge of my case than it would be on my fan due to its airflow optimized nature. But it actually isn’t, because the relevant piece of information is where the air is going, not where the air is coming from. So a fan that is directed to blow air directly out of a heatsink (not through it, or to another fan) is actually a very similar application to a case fan. So that is why I decided to use airflow optimized fans, specifically Arctic F12 fans for this experiment.
Obviously, having a third fan on the CPU cooler and having an exhaust fan right behind it will have the best results, and obviously having a third fan on the cooler directly will be better than having a third fan as an exhausting case fan, but the point of this experiment is just to see by how much.
Data
So first, here’s my no fan data: (No third fan on CPU cooler and no exhaust fan on case)
And here’s my data with an NZXT Aer P stock fan on the back of my case:
The min and max CPU temps are noticeably lower with an exhaust fan, even if it is a stock fan. It’s not even close, as with no fans you had consistent high 60 max temps, and now you are barely hitting the low 60’s on average.
If you replace that with an Arctic F12, a slightly higher performance fan, you get slightly better temps as well, as your max temps are, at a minimum, in the low – mid 50’s. With this same Arctic F12 positioned as a third fan directly on the cooler rather than as a case exhaust fan, you get similar results:
The two lowest max temps in the last two trials are only a couple of degrees apart. Overall, the results with a third fan on the exhaust vs. a third fan only on the cooler directly are surprisingly similar. Obviously, the best performing setup will be the kind with 4 fans in total:
All the max temps were less than 55 degrees, which is not true for any other trial. The orientation of this trial (only this trial) allows for an advantage for a static pressure fan as the third CPU fan (not for any other fan) over an airflow one, since that fan blows into the exhaust fan, and static pressure fans perform better than airflow fans when blowing air into another fan. So that may have yielded further temperature drops, but I did not have an extra static pressure fan on hand so unfortunately I could not account for that.
Overall, I think these results prove that having a third fan if you can put three fans on your heatsink is fun and actually gives you some sort of results, it’s not just for show. Not only that, but these tests were done in video games, which aren’t that CPU intensive, at least not compared to things like video editing or compiling demanding searching algorithms or something. If you do CPU demanding activities like those more often, the performance gains will only be amplified. If you have to decide between adding the third fan on your case or on the end of your cooler, if you want to purely optimize for CPU thermals, put it on your cooler. If you want to optimize for overall case airflow which will assist all your components, but just affect your CPU slightly less, go for putting it on your case. I wasn’t expecting this, but putting a third fan on your cooler AND having an exhaust fan right behind it has a surprisingly high performance jump. Again, that only gets amplified when you do tasks that are even more CPU intensive than Apex Legends. This means that it might actually be worth it, though I had initially just decided to test it because I thought it would be fun. Again, using this configuration benefits from having the third CPU fan be a static pressure fan, since it is blowing air into another fan rather than just into empty space.
