Samsung 990 PRO vs Samsung 9100 PRO

The short answer

Buy the Samsung 990 PRO: the two score the same among NVMe SSDs (100/100) and it costs about 8% less, up to 16% at 4TB. Paying more for the Samsung 9100 PRO buys nothing you can measure.

• •Samsung 990 PRO is cheaper at 3 of the 3 shared sizes: 5% at 1TB ($235.99 against $249.00), 3% at 2TB ($386.00 against $399.99) and 16% at 4TB ($839.95 against $994.25).
• •The Samsung 9100 PRO is a PCIe 5.0 drive against PCIe 4.0 for the Samsung 990 PRO. It needs a matching M.2 slot to reach its rated speed, and in games the gain is a fraction of a second on the longest loads.
• •On paper the Samsung 9100 PRO reads 99% faster, 14,800 MB/s against 7,450. Both are far past the 2,400 MB/s that console-era streaming is built around, so that gap shows up in file copies rather than in loading screens.
• •Buy the Samsung 990 PRO, best value at 4TB where it saves $154.30. Choose the Samsung 9100 PRO instead for a PCIe 5.0 interface and a rated read 99% higher, worth the premium on a drive you will keep near full or write to hard.