I bought the new Samsung 980 Pro 1TB (PCIe 4.0) and put in the Lenovo Yoga Slim 7 (PCIe 3.0), I saw only ~10% decrease in raw performance : r/AMDLaptops
SAMSUNG 980 PRO M.2 2280 2TB PCIe Gen 4.0 x4, NVMe 1.3c Samsung V-NAND Internal Solid State Drive (SSD) MZ-V8P2T0B/AM - Newegg.com
Samsung 980 Pro NVMe SSD review
SAMSUNG 980 PRO M.2 2280 2TB PCIe Gen 4.0 x4, NVMe 1.3c Samsung V-NAND Internal Solid State Drive (SSD) MZ-V8P2T0B/AM - Newegg.com
Samsung 980 Pro Review - CGMagazine
Cache Size Effects - The Samsung 980 PRO PCIe 4.0 SSD Review: A Spirit of Hope
Samsung 980 Pro NVMe SSD review: PCIe 4.0 for the win
Question - Random writes on 980 Pro (PCIe 3.0 x4) | Tom's Hardware Forum