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 PCIe 3.0 NVMe 1TB Internal SSD | Nebraska Furniture Mart
Samsung 980 Pro Review: PCIe 4.0 NVMe is Here
Cache Size Effects - The Samsung 980 PRO PCIe 4.0 SSD Review: A Spirit of Hope
Sequential IO Performance - The Samsung 980 PRO PCIe 4.0 SSD Review: A Spirit of Hope
Question - Random writes on 980 Pro (PCIe 3.0 x4) | Tom's Hardware Forum
Samsung 980 PRO NVMe SSD on PCI-e 3.0, only 1786 MB/sec read speed : r/techsupport
The Samsung 980 SSD Spotted: A DRAM-Less PCIe 3.0 x4 SSD | Tom's Hardware
Mixed Read/Write Performance - The Samsung 980 PRO PCIe 4.0 SSD Review: A Spirit of Hope
Samsung's fast, PCIe 4.0-ready 980 Pro SSD can future-proof your PC build - The Verge
Samsung 980 PRO Review: A Powerful PCIe 4.0 NVMe | Dong Knows Tech
Samsung 980 PRO PCIe 4.0 NVMe SSD Review - StorageReview.com
Samsung 970 EVO vs 980 Pro SSD: Which one should you choose? - SSD Sphere