Little late but might be of interest.
I've found filling front of normal tower case with good high-pressure fans and blocking all openings in front not covered by fans allows air fans push into case to flow on through case instead of leaking thru holes and going in circles.
This creates a sealed panel between intake and exhaust sides of fans so all all they push into case has to flow on through case and out.
Our cases only flow as much air in as they have flowing out. It's the 'every action has an equal and opposite reaction' law of physics. Science of airflow is named 'fluid dynamics' .. because air flow is same principle as water flow. Think of case airflow as water. Think of case as a van in bottom of a pond vs case in a room. Van windows are case vents. If we open 2 front windows (vents) and 2 back windows (vents)and put propellers (fans) in front windows pushing water into van it, we will have same amount of water flowing out as we have flowing in.
Using top vents from front to middle of CPU cooler disrupts case airflow.
Top exhaust vent fan pulls air out removing cool air coming in front and replacing it with heated air coming off of GPU
Top intake man pushes air down disrupting front to back flow in front of cooler fan.
Back of top exhaust fan and front of top intake fan create airflow circle because air from high pressure side of fan exhaust moves to low pressure intake side of fan thus creating circling airflow.
Remove all PCIe back slot covers to increase rear vent area around GPU
This will give you better front to back airflow around GPU moves GPU heated exhaust back and out of case so it gets cooler air.
Every degree warmer air is entering coolers results in component being same degrees hotter, so the cooler we keep airflow to coolers the better.
Using intake and exhaust fans is same principle as push / pull fans on coolers / radiators.
At same noise level single push fan moves same amount of air as push / pull fans because 2x fans make about 3dB more noise push fan.
Increase in airflow of push / pull fans is basically same as single fan spinning faster at same dB as 2x fans.
CLC/AIOs don't really cool much if any better than good air cooling.
Main reason users see lower temps with CLCs is because radiator is mounted as either intake or exhaust on vents thus creating additional case airflow with lower temp air flowing through radiator.
Setup case with good airflow so component coolers get air within a couple degrees of room ambient and components will be as cool as on CLC.
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