Question top radiator in or out airflow, side open

[angry.pidgeon]

Hello.

Just noticed I've been sucking up air through the top radiator of the CPU liquid cooling system, and pushing it into the PC case, who's side I keep open...

Now that I think of it, this benefits the CPU since the air passing through the radiator should be the cooler room temperature, but the GPU is the one that heats up the most, and the CPU liquid cooling is blowing right into it. I have reached GPU temperatures of 80-90 but never crashed AFAIK, and nVidia claims these are normal temperatures (for GTX 690). I don't seem to remember seeing the CPU even in top stress exceed perhaps 75 degrees, even in hot weather

On another note, blowing the air through the top radiator means replacing the air inside the case and around the GPU at a slower rate, which could overall result in even higher temperatures

The science I found so far, meaning the tables in the following links, show I've been running the worst setup for 10 years 🤣 (AIO intake, case fans intake, but side open)

How to place your liquid cooler

The guidance to demonstrate the best liquid cooler placement.

www.msi.com

The Ultimate PC Airflow Guide: Setting up Your Rig for Optimal Cooling – Voltcave

Airflow isn’t the most glamorous part of PC building, but it’s one of the most important. Our PC airflow guide will help you optimize cooling.

voltcave.com

Think I should switch to AIO exhaust, sys fans intake? While the CPU difference is unnoticeable (3 degrees), the GPU difference (4.8 degrees) might matter since it already goes into the extremes? It also suppose to be win-win

I can tell by looking at the pictures that:
1. front mount maximizes liquid surface contact and thus temperature transfer with the radiator
2. taking the "cold" liquid from the bottom works better than taking it from the top where the "hot" liquid rises when returning from the CPU

Still, I can't mount in front because I have to remove the front fans, which I would have to put on top, if it's possible at all given their size

What do you think/know?

 

[MrLitschel]

The rule of thumb I always follow regardless of whether a AIO/CPU Radiator is attached.

Bottom & Front Fans - Intake
Back & Top Fans - Exhaust
If any fans are on the side of the case - Exhaust if at the rear/Intake if closer to the front

This usually gives the maximum air flow through most cases. The location of Hard Drive Enclosures and other internal cards may obstruct some flow. This comes more important with smaller cases

 

[angry.pidgeon]

Exhaust is not really a factor in my pc because I keep the case open, so the air gets out any way it can. My old PC has only one front bottom fan blowing in the direction of the GPU, which blows downwards which is blocked, so it goes out sideways. The top of the GPU is hot so hot air rises, which is pushed sideways as well by the top intake

My new PC case has mesh everywhere, plus I will keep it open as well. Has 2 huge intake front fans, bottom will be half blocked as usual by the PSU which will intake from bottom and exhaust out so as to not interfere with the GPU. I rather not have the GPU blow hot air into it and through it either. Never bothered about the PSU temperature

So the bottom question is since the rest wouldn't matter, should my top radiator blow air into the (back of the) GPU, or vent to the top of the pc which hardly affects the GPU (cooled by front intake as well). I can't tell by intuition if that will make up for a more stable GPU at high temperature, or not, and too lazy to experiment Only way I'll try is if the GPU gets too hot, but reviews say it shouldn't happen

 

[CountMike]

Exhaust is not really a factor in my pc because I keep the case open, so the air gets out any way it can. My old PC has only one front bottom fan blowing in the direction of the GPU, which blows downwards which is blocked, so it goes out sideways. The top of the GPU is hot so hot air rises, which is pushed sideways as well by the top intake

My new PC case has mesh everywhere, plus I will keep it open as well. Has 2 huge intake front fans, bottom will be half blocked as usual by the PSU which will intake from bottom and exhaust out so as to not interfere with the GPU. I rather not have the GPU blow hot air into it and through it either. Never bothered about the PSU temperature

So the bottom question is since the rest wouldn't matter, should my top radiator blow air into the (back of the) GPU, or vent to the top of the pc which hardly affects the GPU (cooled by front intake as well). I can't tell by intuition if that will make up for a more stable GPU at high temperature, or not, and too lazy to experiment Only way I'll try is if the GPU gets too hot, but reviews say it shouldn't happen

With case side opened it pretty well negates effects of case fans and airflow,. GPUs benefit most because they don't depend of airflow and take air directly from outside. Air always takes path of lesser resistance and open case is just a big hole which would provide 99% of fresh air.

 

[MrLitschel]

Exhaust is not really a factor in my pc because I keep the case open, so the air gets out any way it can. My old PC has only one front bottom fan blowing in the direction of the GPU, which blows downwards which is blocked, so it goes out sideways. The top of the GPU is hot so hot air rises, which is pushed sideways as well by the top intake

My new PC case has mesh everywhere, plus I will keep it open as well. Has 2 huge intake front fans, bottom will be half blocked as usual by the PSU which will intake from bottom and exhaust out so as to not interfere with the GPU. I rather not have the GPU blow hot air into it and through it either. Never bothered about the PSU temperature

So the bottom question is since the rest wouldn't matter, should my top radiator blow air into the (back of the) GPU, or vent to the top of the pc which hardly affects the GPU (cooled by front intake as well). I can't tell by intuition if that will make up for a more stable GPU at high temperature, or not, and too lazy to experiment Only way I'll try is if the GPU gets too hot, but reviews say it shouldn't happen

Pushing the air down towards the cpu from the top isn't efficient.

When you pull the air up through the top., it will draw the some of the hot air from the GPU and CPU with it. Tte cool air from around the case will naturally be drawn inwards to the GPU when drawing the hot air up and out. The rear case fans will pull additional hot air from the CPU area while the front fans pushing in the cool air from the front.

Unless the case is specifically made as an "Open Side" case, removing the side panels can have a detrimental effect to the airflow that was intended. For example, air blown in from the front case fans may be inefficient to reach the CPU/GPU area because it is just venting out the open side. Fans placed at the bottom to pull air in would be subjected to the same negative effect. Rear and Top Case fan will still exhaust the case but less efficiently.

 

[Misgar]

The only time I'd blow hot air from a radiator into the case would be if I was forced to mount the radiator vertically on the front panel. Even then I'd be very unhappy. The whole point of ventilation is to remove heat from inside the case, not add to it.

I only remove the side panel on a running computer as a last resort. It negates all the filters on the intakes to the fans. With the side panel off, most of the case fans are redundant.

The only time I've deliberately heated a computer is when I added heater strips with a thermostatic switch to a hard disk drive in a system designed to operate down to -10C.