DDR4 vs DDR5 for RTX 4090 at 1440p: Stick with DDR4, the upgrade isn't worth it

Your RTX 4090 is already CPU-bound at 1440p, not RAM-bound. DDR5-6000 might net 3–5% in a few CPU-heavy titles, but usually it’s within the margin of error. The real cost is $300+ for a new motherboard and RAM you won’t feel. That money is better spent on a 4K monitor or a faster CPU.