https://us.community.samsung.com/t5/Monitors-and-Memory/Samsung-990-PRO-2TB-Performance-Degradation-After-7B2QJXD7/m-p/3403545#M17537 <P>I hesitate to even conjecture...how would I be able to test the M2_1 slot of my motherboard to know that it's OK?&nbsp; That might explain why the 4TB in a different slot performs so differently and might even explain the Power On Hours discrepancy...but, then again, it might not.&nbsp; If you have a recommendation for testing the slot, let me know.&nbsp; I could swap the 2TB and 4TB drives and repeat the benchmarking, but I'm not confident that would prove anything.&nbsp; Otherwise, I bought the 2TB and 4TB 990 Pro's (and the X870e Taichi motherboard) in February 2025.</P><P>Following up, I found a review of the 990 Pro 2TB that does a very good job of explaining SLC impact on benchmarking metrics.&nbsp; My changing the fio runtime parameter is equivalent to looking at performance with different amounts of data written, as discussed in the review; effectively, I'm seeing performance either before or after the SLC cache is exhausted.<BR /><BR />Here's the link:&nbsp;&nbsp;<A href="https://www.techpowerup.com/review/samsung-990-pro-2-tb/" target="_blank">https://www.techpowerup.com/review/samsung-990-pro-2-tb/</A></P> Mon, 10 Nov 2025 22:42:15 GMT SFdrifter 2025-11-10T22:42:15Z