Now it's crystal clear what happened.
This is a prime example of
form over function.
Look good first, work second.
You see, there is something very, very important that you must know about PCs: The fans need to take air to be able to blow air.
Airflow must be clear, where the cool air goes in, where the hot air goes out.
Your case, however, is bad at it.
There are some problems with your PC:
- As you can see, the 3 fans are choked, because they have nowhere to take air to be blown through the radiator, since it's too close to the beautiful tempered glass, resulting in the fans only spinning like a fidget spinner, hardly blowing any air. That's one case of form over function.
- There is no intake fan in there. The back fan is exhaust, and the radiator fans are choked. This results in not only a weak airflow, but also a horrible negative air pressure, which results in a high dust buildup level.
How to fix it:
- Buy more fans. Buy 3 more. Place them at the bottom of the case with intake configuration. This is the best fix, but costs more money.
- Change the back fan into intake. The airflow is still weak, and dust might come in from the back, but it's better than your current configuration, and you don't need to buy new fans. After that, move your radiator and the fans to the bottom. The fan configuration is exhaust. You will fight convection, but it's better than configuring the fan at intake.
EDIT: On a second thought,
DO NOT MOVE THE RADIATOR TO THE BOTTOM. It's dangerous, the GPU fans and the radiator fans would be fighting for air.