Optimal fan setup

There may be no legitimate answer to this one since I imagine it varies from setup to setup but my question is simply what is the optimal setup for my fans?

 

A little info on my setup:

 

I have 6 Corsair LL fans and an H100i V2 inside a Corsair Graphite 780t. Cooling wise it actually stays quite cool, in part due to the size of the case, however, I feel my CPU isn't being cooled efficiently.

 

Currently, three of the fans are in the front of the case being used as an intake, two are on top of the case being used as exhaust and the final fan is on the back being used as exhaust. The H100i is attached to the two top fans, this is because it is only two slots tall so it fits in here perfectly.

 

Is this fine? Will I be able to get more efficient cooling if I moved the cooler to the front fans or perhaps changed the top fans to be intake as well?

In general, having the radiator as intake is better for coolant (and CPU) temperatures at the expense of internal case temperatures.

 

In general, having more intake is better than more exhaust (positive pressure) ... but not a whole lot more. You want it relatively balanced with a tendency towards positive pressure, not negative. It keeps the system cleaner.

 

That said, as you suspect, it varies from setup to setup. Many folks (including myself) have their radiators as exhaust. This can be due to case design or simply because you don't want to dump the excess CPU heat directly into the case. One challenge with this, however, is the GPU waste heat. With the CPU being water cooled, the largest producer of heat is the GPU and GPUs can put out a LOT of heat. You didn't fill out system specs so we can't tell if GPU heat may be an issue for you (hint, hint).

 

So ... before you start moving things around ... what kind of temperatures are you seeing that lead you to believe that you aren't cooling effectively? We'd want both CPU and coolant temperatures. What's your ambient/room temperature? How much to temps rise after an extended gaming session (assuming that you game)? Have you considered some bottom fans as intake?

I agree you should take a hard look at H100i v2 Coolant Temperature and general ambient case temperature before moving things around or making fan changes. The 780T is a pretty clear front in/top & rear out kind of case. Not likely to see large differences by switching fans unless you are willing to really blast them, something that may not be overly beneficial.

Sorry about not providing the additional system specs, I did fill them out when creating the account, however, I'll provide them here.

 

Motherboard: Gigabyte GA-Z270XP-SLI

CPU: Intel I7 7700K, Standard Clock is 4.2, however, the Motherboard auto clocks this to 4.5

GPU: MSI Geforce GTX 1080 8G

RAM: 4x8gb Corsair Vengence RGB

 

Generally, the GPU will reach temps ranging from 70 in a normal game to 80 in a really intensive game. I actually have the GPU's temp limit raised from 83 to 92 so it's not actually thermal throttling. I have this placed in the fourth PCIe slot so that it isn't straight under the CPU. Obviously, this probably makes little difference given that heat rises but every little helps.

 

CPU wise it varies, right now while idling its sitting at the mid-40s which seems way too hot for idle temps. The temp sensors connected to my commander pro say the inside of the case is sitting around 30-35 degrees and it's been pretty hot recently so I imagine the ambient temp is skewing the results a little. The coolant is staying at around 35 degrees, based on what you've both have said I imagine this implies the coolant is being cooled efficiently enough, I am worried a little about the CPU temps though. In terms of how the temps change while gaming, it's entirely dependant on the game. If they use a lot of GPU and not a lot of CPU i've seen that the temps of the CPU only go up a little however if they use the CPU heavily, games like GTA5 for example, the CPU will go up a lot. I've not managed to get exact values for this but I did record it going into the high 80s/low 90s on one occasion recently.

 

In regards to the idea of having bottom fans, I can do this, however, I was reluctant in case it cause some issues with the airflow. I believe the 780t has room for two bottom mounted fans, I will put two in to see what how this goes.

 

My Vengence RAM is also sitting around 40 degrees with the Dominator cooling fan on them.

 

Once the weather cools down a little I am going to take another look at the temps I'm getting to be safe. Right now I can't say if the CPU is getting hot due to it not being cooled well enough or just because the ambient temps are high.

What is your coolant temperature? That's a pretty important variable here.

 

Also, where in the case are you measuring temperature? It can vary pretty widely, especially with a beefy GPU. Also, are you measuring the radiator intake temperature? That'll provide us with a baseline on how well your radiator is cooling when compared to the coolant temperature.

Coolant temperature sits around 30 degrees, sometimes going up to 33.

 

I am measuring the temperatures based on a few different things. The way I'm measuring the CPU temp is from what the CPU is reporting itself. The case temp is being measured by temp sensors connected to my Commander Pro which seem to sit between 30 and 35 degrees.

 

I have a temp sensor in the top of the PC above where the radiator exhausts the air, while idle this one sits at 32 degrees.

 

The CPU is sitting at around 40-45 degrees currently.

Typically in cases of blocked or partially blocked flow, we see higher radiator temperatures than what you are reporting.

 

Also, monitoring the temperature of the radiator intake is super-helpful. Personally, I have one of the thermistors from the CoPro between the fan and the radiator ... on the intake and exhaust (mine is configured as push/pull).

 

What's your vCore (vCPU in Link/iCue)? It's jumpy so you need to watch it ... how high does it get? And what's your CPU utilization?

The GPU temperature itself is really only going to be affected by its own fans. Sure, if the case is 10C cooler the GPU starts off 10C cooler as well, but typically you can only affect that kind of change by altering the entire room temperature. What's more problematic is when the GPU is throwing waste heat everywhere and it raises the case temperature unnecessarily. That becomes additive for all the other components.

 

Your coolant temp can only be as low as your case temperature. The low 30s in the hot Summer is the best you can do in a room getting into the upper 20s. All my hardware is water cooled and the heat dumped directly out. Even still, it is hard for me to keep a baseline below 29-30C in the Summertime.

 

Bottom fans might help or at the very least let you slow down the front fans while gaming. However, I don't really see any heat management issues with your set up or hardware. I think most likely you are looking at classic Kaby/Coffee Lake CPU behavior management issues, something everyone runs into. Rather than hardware, take a look at the peak Vcore reading as suggested above. How are you set up? Stock/Auto settings? Overclock? Adaptive or Manual voltage? There are a few tweaks you can do to rein in the CPU behavior.