Will upgrading to DDR5 RAM fix 1% low stutters in games like Cyberpunk 2077?

Not really. The difference in 1% low fps between DDR5 and DDR4 in Cyberpunk 2077 is usually within single-digit percent — not enough to smooth out stutters. DDR5’s worse latency compared to well-tuned DDR4 can even cause more stutters in some games. A faster GPU or a CPU with more L3 cache (like AMD’s 3D V-Cache chips) will help 1% lows far more than swapping RAM.