H100i V2 Exhaust or Intake?

Read the FAQ but still to wrap my head around why my H100i V2 instruction manual said to install the fans to blow air up across the radiator (exhaust.) I have a 760T case so the cooler fans/radiator are mounted at the top. Seems like that exhaust mode would be pulling the heated air from the GPU/CPU & Power regs. area and blowing it across the radiator. Wouldn't drawing in ambient air that's ~24C be better?

Actually, if I recall the installation manual correctly, it suggests that intake will give you better performance. And, in general, it will. It will, however, be dumping the waste heat from the CPU into the case, warming up the internal temperature for all of your components.

 

Many folks configure their coolers as exhaust. I have different system configured as both intake and exhaust, depending on the system and the overall airflow situation that I'm trying to achieve. When configured as exhaust, you do have to make sure that you manage the heat from the internal components, especially the GPU. Properly configuring the speed of the case airflow fans, especially the exhaust fan, is essential to this.

 

As with many things, there is no single, absolute right answer for every situation. It's all a fine balancing act.

Thanks!

I'll give it a try as intake and see how it performs (since I have air conditioning now, I have more control over ambient air.)

 

I don't remember the wording in the manual and didn't see a place on the Corsair site to download it (wanted to avoid searching through storage boxes to find it.)

 

I have two intake case fans blowing on the drive bays, one at the bottom of the case and one under the power supply (both intakes), and one at the back of the case as exhaust.

 

Can the H100i fans be mounted on top of the radiator to blow through (the radiator) or should it be below to draw air through the radiator (seems the former would be the way to go)?

Again, push or pull will be the same from a performance perspective ... they will get the same amount of air through the radiator. However, having the fan pull air through the radiator does make the radiator easier to clean from dust - you won't have to remove the fans to clear out the dust.

Seems that pulling/pushing cooler (ambient) air through the radiator would be better though. Maybe I'm confusing the issue -- I'm talking about the the air intake to the radiator, which can be push/pull from outside or inside of the case. The air inside is much warmer than outside so the cooler air should cool the liquid more (by using cooler air.)

I thought that you were asking about using the fans to "push" or "pull" through the radiator. You can do either, regardless of exhaust/intake configuration.

As for whether it is intake or exhaust ... I've already answered this.

 

However, looking at only the radiator and CPU is myopic. You have other sources of heat and other things to consider when putting together your system's cooling. Yes, intake cools the radiator better. But it also dumps the CPU heat into the case, where it heats up the GPU, VRMs, memory and drives.

No, I was talking about pushing/pulling ambient air through the radiator intead of pushing/pulling air from inside the case through the radiator. The mounting instructions I have said to mount the fans under the radiator with the air direction pointing up. This pushed the warm air into the radiator, which didn't seem right.

You're looking too deeply into this. First, blowing 26C air versus 29C air across the radiator fins will make no difference for your coolant and add-on CPU temps. The air is not "cooling" the liquid. The fans are helping to move the heat slowly being released from the radiator to somewhere else. The air speed will impact this more than small temperature differences and even then, fan speed isn't overly critical.

 

What is more likely to have an impact on your general coolant temperature is the local environment. The top 3 inches of your case may be a few degrees warmer than the bottom or front. That local temperature is the effective minimum coolant temperature, even with zero load. If you mount in the top of the case, using the fans as intake or exhaust is likely to make little difference in a CPU only load. However, you want to consider if a single rear fan will be capable or removing the GPU and CPU waste heat you are likely to see in mixed load conditions. With a single exhaust fan, it;s volume exchange rate will be the limitation for the entire case. It's not terribly difficult to take the radiator down and flip the fans and experiment for yourself. As for the instructions, they are typical multiple step picture directions. You are not going to get an elaborate explanation that covers every model, size, case placement, and in consideration of your other hardware. It's too many variables to cover, so you get the generic disclaimer.