In terms of case temperatures, how significant is 55 CFM?

[ProtoflareX]

I'm sure there are innumerable factors that go into determining something like this, but hopefully there's still an opportunity for a rough estimate here. I'm currently trying to determine if it is advisable for me to opt for silence over air flow with my case's top exhaust fan slots. I can opt for one 200mm fan with a CFM of 110, or two 140mm fans with a combined CFM of 165.04. The two fans would, of course, be louder, but move more air. My choice will ultimately be decided by the temperature difference between those two CFMs. Like I mentioned earlier, I'm sure the answer to this question varies based on the environment and a bunch of other things, but roughly, would you guys say the temperature difference caused by 55 CFM leans more toward negligible or significant?

[Crunchy Dragon]

My guess would be negligible, since case airflow usually doesn't determine much about component temperatures unless it's really bad.

 

I ran my system without two fans for a short while, I didn't notice much of a temperature difference between having them on and having them off.

Granted I had different GPUs, I know for a fact my GTX 780 dropped a good few degrees between having the intake and not having the intake.

[Jurrunio]

200mm fan on the top? never heard of that

 

but the temperature difference will depend on the overall layout. If there's a big heatsink on top of the CPU then that 55CFM will give a significant difference. Otherwise, the difference should be small, not even that noticeable.

[ProtoflareX]

2 minutes ago, Crunchy Dragon said:

My guess would be negligible, since case airflow usually doesn't determine much about component temperatures unless it's really bad.

 

I ran my system without two fans for a short while, I didn't notice much of a temperature difference between having them on and having them off.

Granted I had different GPUs, I know for a fact my GTX 780 dropped a good few degrees between having the intake and not having the intake.

Interesting... Sounds like I'm about to save money and my ears.

[Crunchy Dragon]

1 minute ago, Jurrunio said:

200mm fan on the top? never heard of that

I recall the NZXT Phantoms having space for 200mm fans on top...

EDIT: yeah, they did:

Quote

Fan Support

FRONT, 1 X 140mm REAR, 1 X 120mm (included) SIDE, 2 x 120mm, 1 x 200/230 (2 x 120mm included) TOP, 2 X 200mm (1 x LED 200mm included)

https://www.nzxt.com/products/phantom-white

[ProtoflareX]

1 minute ago, Jurrunio said:

200mm fan on the top? never heard of that

 

but the temperature difference will depend on the overall layout. If there's a big heatsink on top of the CPU then that 55CFM will give a significant difference. Otherwise, the difference should be small, not even that noticeable.

There will, indeed, be a big heatsink on top of the CPU, specifically, the Noctua NH-D15. So, in that case, the 2x 140mm would actually be better?

[Jurrunio]

Just now, Crunchy Dragon said:

I recall the NZXT Phantoms having space for 200mm fans on top...

I just know some Cooler Master case and thermaltake Core V1 and V21 supporting one in the front, but not the top.

 

Just now, ProtoflareX said:

There will, indeed, be a big heatsink on top of the CPU, specifically, the Noctua NH-D15. So, in that case, the 2x 140mm would actually be better?

Yes

 

or just let the 140mm fans run slower for the same performance as the 200mm at full blast

[ProtoflareX]

4 minutes ago, Jurrunio said:

I just know some Cooler Master case and thermaltake Core V1 and V21 supporting one in the front, but not the top.

 

Yes

 

or just let the 140mm fans run slower for the same performance as the 200mm at full blast

Out of curiosity, why does the presence of a large heatsink increase the impact of the exhaust fan's CFM? I want to expand my knowledge of case cooling.

[Jurrunio]

4 minutes ago, ProtoflareX said:

Out of curiosity, why does the presence of a large heatsink increase the impact of the exhaust fan's CFM? I want to expand my knowledge of case cooling.

because the alternative is watercooling, which includes a radiator somewhere else doing the heat exchange. Extra fans dont increase airflow past the heat dissipation area in that case.

[ProtoflareX]

9 minutes ago, Jurrunio said:

because the alternative is watercooling, which includes a radiator somewhere else doing the heat exchange. Extra fans dont increase airflow past the heat dissipation area in that case.

Interesting... That answer actually gave rise to another question. Let's assume that the CPU heatsink is in the path of the air entering the case from its intake fans; in this case, how significant is a 40 CFM difference between two different intake fans in regards to CPU / case temps?

[Jurrunio]

36 minutes ago, ProtoflareX said:

Interesting... That answer actually gave rise to another question. Let's assume that the CPU heatsink is in the path of the air entering the case from its intake fans; in this case, how significant is a 40 CFM difference between two different intake fans in regards to CPU / case temps?

not sure how is this different to the first question (question in the topic)? You mean changing fans that sit in front of the radiator, 1 setup includes a 200mm fan while the other setup uses a pair of 140mms?

[ProtoflareX]

27 minutes ago, Jurrunio said:

not sure how is this different to the first question (question in the topic)? You mean changing fans that sit in front of the radiator, 1 setup includes a 200mm fan while the other setup uses a pair of 140mms?

Oh no, I'm now referring to a different set of fans entirely. My first question dealt with how a 55 CFM difference between one 200mm exhaust fan and two 140mm exhaust fans would affect case temperatures. If I understood what you said correctly, the difference would be negligible if I were using liquid CPU cooling since the dissipation of the CPU's heat takes place away from the exhaust fan. However, since I am using air cooling, the presence of a large heatsink directly beneath the exhaust fan (or fans) increases the impact of that increased CFM significantly. Now I'm wondering if that applies to intake fans as well. The case's stock intake fans are two 200mm fans with a combined CFM of 180. The NH-D15's heatsink is so large, that it is hit directly by the air that the intake fans blow into the case. As a result of that, I am wondering if upgrading the two stock fans to stronger fans that have a combined CFM of 220 would have a noteworthy effect on temperatures.

[Jurrunio]

3 minutes ago, ProtoflareX said:

Oh no, I'm now referring to a different set of fans entirely. My first question dealt with how a 55 CFM difference between one 200mm fan and two 140mm exhaust fans would affect case temperatures. If I understood what you said correctly, the difference would be negligible if I were using liquid CPU cooling since the dissipation of the CPU's heat takes place away from the exhaust fan. However, since I am using air cooling, the presence of a large heatsink directly beneath the exhaust fan increases the impact of that increased CFM significantly. Now, I'm wondering if that applies to intake fans as well. The case's stock intake fans are two 200mm fans with a combined CFM of 180. The NH-D15's heatsink is so large, that it is hit directly by the air that the intake fans blow into the case. As a result of that, I am wondering if upgrading the two stock fans to stronger fans that have a combined CFM of 220 would have a noteworthy effect on temperatures.

oh the front intakes? The difference there isn't noticeable (if any). The fans on the cooler itself is much more effective in pushing air compared to the front intakes, being this close to the heatsink in comparison makes the front intakes largely irrelevant (unless you use very slow fans of course).

[ProtoflareX]

37 minutes ago, Jurrunio said:

oh the front intakes? The difference there isn't noticeable (if any). The fans on the cooler itself is much more effective in pushing air compared to the front intakes, being this close to the heatsink in comparison makes the front intakes largely irrelevant (unless you use very slow fans of course).

So in summary, because I am using air cooling, which involves a large heatsink being directly beneath the top exhaust fan (or fans), the increased CFM of two 140mm exhaust fans as opposed to one 200mm exhasut fan will have a noticeable effect on the case and CPU temps. In addition to that, since the case's two front intake fans are further away from the heatsink than the top exhaust fans and the fans that are attached to the heatsink itself, replacing them with higher CFM fans would not have as much of an impact as with the exhaust fans? Did I get that right?

[Jurrunio]

1 hour ago, ProtoflareX said:

So in summary, because I am using air cooling, which involves a large heatsink being directly beneath the top exhaust fan (or fans), the increased CFM of two 140mm exhaust fans as opposed to one 200mm exhasut fan will have a noticeable effect on the case and CPU temps. In addition to that, since the case's two front intake fans are further away from the heatsink than the top exhaust fans and the fans that are attached to the heatsink itself, replacing them with higher CFM fans would not have as much of an impact as with the exhaust fans? Did I get that right?

Yes that's what I meant. Stronger intake fans on the front can potentially help with GPU temps more though, since the card itself doesnt have fans nearby helping to blow away warm air.

[ProtoflareX]

8 hours ago, Jurrunio said:

Yes that's what I meant. Stronger intake fans on the front can potentially help with GPU temps more though, since the card itself doesnt have fans nearby helping to blow away warm air.

Interesting. In that case, maybe it would be worth it to invest in the stronger fans after all. I'm looking to build a rig that won't need to be replaced for years, and hardware temperatures play a direct role in that. Anyway, thank you to you and the other contributors for answering my questions. I've selected one of your earlier comments as the thread answer.