Discussion 120mm rad vs 240mm rad with 1 fan

[shhan9088]

I've been looking round for some ITX cases and found that some cases (Warhead Sans mk1 and Micro) will support 120mm rad (with a fan) + extra fan (for airflow), and can support 240mm radiators but with only 1 fan.

In this situation what do you think is the more sensible option to go for?
Here are my rough thoughts this idea:

I imagine the temps at the end of a long stress test would be about the same for both options, with big difference being the time to equilibrium being much(?) longer for the 240mm rad. Which may be a positive aspect. But, due to only having 1 fan in the entire build I guess GPU thermals may suffer as well...? and having 1 fan move air in and out the case may just make the thermals suck?

I'm not entirely sure, hence the post. Would love to hear what you think about the situation.

P.S: I currently have a 10850k and a gtx970 (which I plan to upgrade in the future) in a mid tower case, and I am in the process of converting to an ITX PC. And before I start ordering stuff, I'm trying to make a proper plan on which parts to use.

 

[scatterforce]

Typically, a slim rad with a good fan will outperform a thick rad with a slim fan.

I think the same applies here. More airflow on a 120 rad should outperform a 240 with only a single fan. Now, it does depend on the case.... the Corsair One has decent cooling with only one fan.

edit: typo

 

[tinyitx]

When a rad has no fan, its cooling power is mostly impaired. So, for a 240 rad with only a single fan, that other 50% portion of the fins is almost useless as no air goes through them and natural convection is just meh.

So, I would rather have a 120 rad with a fan and then a second fan to provide more air intake. This could be very useful when the ventilation of the case is determined by pressure (positive or negative).

 

[shhan9088]

Thats a very good point, I guess the 120 set up would most likely result in better overall temps.

 

[shhan9088]

it does depend on the case....

I'm looking mainly at sandwich layout , horizontal cases.
And about the airflow bit; If i use the same fan, shouldn't I be getting the same amount of airflow for both rads? its just the 120 gets 120mm worth of airflow and the 240 also gets 120mm worth of airflow. So I would have imagined that the 240mm would act more as a 120mm + a resevoire of some sort.
But i guess the overall airflow of the case may affect the efficiency of "120mm worth of airflow".

 

[paulesko]

I think it depends on the fan configuration for the case you are using. If your config. is heavily putting air outdside of the case, you will generate an inflow of air through the portion of the rad you have without a fan. On the other hand if you have both fans putting air inside the case, and getting air outside of the case all of them at a similar speed, the amout of air you are forcing to go through the passive rad is not going to be that much, and it will not provide much difference.

I´ve never done it, but looking in my case, I have all the fans as exhaust, (ncase M1) that way I make sure that as much fresh air as possible is going inside through the back of the psu, the back of the mother board and the top of both also. With that, I can get better chipset, ram and VRM temps, which is not something we talk about that much.

 

[shhan9088]

If your config. is heavily putting air outdside of the case, you will generate an inflow of air through the portion of the rad you have without a fan.

Yeah but with the case I'm thinking about the only way air is going to be forced out of the other half of the 240 rad is via the GPU and convection. And it's probably unrealistic to expect much negative pressure to build up with a single 120mm fan.