Perfect Clearance Achieved
The NVIDIA GeForce RTX 4090 (304.0mm) easily clears the Lian Li A4-H2O RGB's 322.0mm maximum GPU length.
Detailed Compatibility Analysis
Will the NVIDIA GeForce RTX 4090 fit inside a Lian Li A4-H2O RGB?
The short answer is Yes. You will have no trouble fitting the NVIDIA GeForce RTX 4090 (304.0mm) inside the Lian Li A4-H2O RGB, which boasts a maximum GPU clearance of 322.0mm.
Clearance and Airflow
With this specific hardware combination, you are left with exactly 18.0mm of physical space between the front edge of the GPU and the front panel (or front fans). This is a healthy amount of breathing room, ensuring your graphics card stays cool and airflow remains unrestricted.
Radiator Warning
If you are just using standard 25mm case fans in the Lian Li A4-H2O RGB, you will have plenty of room to route your PCIe power cables cleanly. However, a push/pull radiator configuration at the front might consume that remaining 18.0mm of space.
Frequently Asked Questions
Does the Lian Li A4-H2O RGB support vertical GPU mounting?
Many modern cases support vertical mounting via an optional PCIe riser cable. However, mounting a thick card like the NVIDIA GeForce RTX 4090 vertically can push the fans dangerously close to the glass side panel, choking airflow. Always check the case manual for specific slot spacing.
What power supply (PSU) do I need for the NVIDIA GeForce RTX 4090?
You should refer to the official manufacturer recommended PSU wattage. When building in the Lian Li A4-H2O RGB, ensure your PSU is not longer than the case's basement shroud clearance, especially if you plan to keep the hard drive cage installed.
How do I calculate clearance if I add a front liquid cooler?
If you install an AIO liquid cooler in the front of the Lian Li A4-H2O RGB, you must subtract the thickness of the radiator (usually 27mm) and the fans (usually 25mm) from the total 322.0mm clearance.