The graphics card "PULSE AMD Radeon RX 6400 GAMING (4 GB)" can be used in a Dell 7090 SFF if some conditions are met. The Dell 7090 SFF usually uses an Intel platform that supports PCIe 3.0, while the RX 6400 is PCIe 4.0. The card should still work, but with half the bandwidth consumption, which should be sufficient for display purposes. It is important to ensure that the SFF computer has a suitable PCIe slot and a sufficient power supply, as the card consumes 55 watts. The BIOS setting should also be checked to ensure that the graphics card is recognised.