What 4K really demands
Native 4K at high frame rates is the hardest job in gaming, and only a handful of cards do it comfortably. The RTX 5080 handles maxed 4K in most titles, and the RTX 5090 does so with headroom to spare for high-refresh 4K panels. AMD's RX 7900 XTX remains a compelling rasterised-4K option with 24GB of VRAM, though it trails on ray tracing.
For many players, playable 4K rather than maxed 4K is the smarter target. The RTX 5070 Ti and RX 9070 XT deliver a great 4K experience with DLSS or FSR at a fraction of flagship pricing, which is why they appear on both this list and the high-end 1440p list.
Do not forget the rest of the system
A 4K flagship needs a CPU and PSU to match. The RTX 5090 in particular pairs best with a fast modern processor and an 850W or larger power supply, and it expects a high-refresh 4K monitor to justify its cost. Pairing a flagship GPU with a slow CPU or a 60Hz panel wastes much of what you paid for.