Dell Optiplex XE4 SFF Compatibility with NVIDIA® RTX™ A400 Graphics card

Re:  I want to know if Dell Optiplex XE4 SFF  is Compatible with NVIDIA® RTX™ A400 Graphics card.

Yes, from the technical capability, the RTX A400 should be support and works with your OptiPlex XE4 SFF.

These are the tested and validated discrete graphics cards for the XE4:  https://www.dell.com/support/manuals/en-us/optiplex-xe4/opti7000mt_xe_ss/gpudiscrete?guid=guid-5dfeef52-0a8a-4f32-984e-5289f718fa2c&lang=en-us

The RTX A400 is a 50w, slot powered card that is similar with those slot powered cards and is within technical specifications of the system Gen 4 PCIe x16 graphics slot.