Anyone switch to 5K2K with the new 45GX990A? How much is the performance loss?

Thinking of upgrading from 3440x1440 to 5120x2160 now that the 45GX950A-B is out. For those of you who made the switch, has the performance hit been noticeable compared to your previous monitor? This will obviously be GPU dependent, I'm running a 5090. Curious how much of a drop you felt and whether it’s been worth it.