What FPS will I get in Path of Exile at 1440p?

At 1440p Ultra native, expect around 180 FPS. With DLSS Quality you can push higher.

Does GeForce RTX 5090 WINDFORCE OC support DLSS or FSR in Path of Exile?

Path of Exile does not currently support upscalers.

Yes — the GeForce RTX 5090 WINDFORCE OC runs Path of Exile at approximately 240 FPS at 1080p Ultra (native, no upscaling).

✓Yes — Excellent

Expected: 240 FPS @ 1080p Ultra (native).