Phanteks P300A - Airflow issues

[Lare111]

I currently have an RTX 3060 Ti (OC'd) and an i7-11700F in the Phanteks P300A. I have 3 x Be Quiet! Silent Wings 3 120mm fans and they are actually great fans in terms of both noise levels and static pressure. The lower front intake fan runs at constant 1100RPM and I can feel cool air exhausting through PCI-slots. However, temperatures could still be better.

I've noticed that both the upper front intake fan and the CPU cooler fan really disturb GPU airflow. I paused Unigine Heaven in a scenario where GPU was heavily power limited (216W), set GPU fan speed to 1500RPM and tried different fan speeds in Argus Monitor. Lower front fan was spinning at fixed 1100RPM, exhaust fan was spinning at 1000RPM and I only changed upper front fan and CPU fan speeds. Here's my results:

Front fan 1500RPM, CPU fan 1500RPM = GPU temps 79C
Front fan 1500RPM, CPU fan 700RPM = GPU temps 76C
Front fan 700RPM, CPU fan 700RPM = GPU temps 72C
Front fan 0RPM, CPU fan 700RPM 0 GPU temps 69C

What's going on? Why do the fans above the GPU increase it's temperature so much? Do they prevent the GPU from getting enough cool air? Now I can either choose good CPU or good GPU temps. Those temperatures aren't alarming yet but it's winter and pretty cold. I might have some trouble in summer. I thought that this case was supposed to have decent airflow.

Things I tried:
- Opening the side panel = very cool temps and quiet PC
- Removing the front panel = no difference in temps or noise levels
- Adding one additional exhaust one on top = no difference in temps but louder PC
- Adding 140mm front fans = annoying humming noise (turbulence?) since the frame partially blocks 140mm front fans
- Increasing the lower fan RPM = better GPU temps but more noise

 

[doyll]

These new GPU coolers seem to be problematic, often disrupting case airflow / increasing RAM temp. While I've lots of case airflow experience with older GPU I have none with new ones so can't help much. Have you tried taping off all openings in front fan panel not covered by fans? This usually helps because once these openings are blocked the air front intake fans is flowing into case has to move on through case to go out back or top vents instead of leak around thru these holes in front of intake fans and go in circles. Could try removing unused PCIe back slot covers. Even vented ones restrict airflow by more than 50%. With older GPUs this usually helps, but it's hit & miss with these new ones.
Attached link below to basic guide to how airflow works and how to optimize case airflow might be helpful too.
https://forums.overclockers.co.uk/t...-i-put-my-temp-sensor.18564223/#post-26159770