NVMe vs SSD RAID 0

[Yahoo Mama]

I have a 500 GB samsung 970 Evo nvme ssd as my boot drive and two 2 TB samsung 860 evo sata ssds in raid 0 via the raid controller on my msi B550 gaming pro motherboard. As expected, when I run crystal disk mark, the nvme is much faster. However, when I transfer large files from one to the other, the transfer speed to the nvme is just under 1 GB/s, and doesn't fall off really at all. Maybe that's a little low, but I don't always expect real-world performance to be the same as benchmarks. However, when I transfer the same file from the nvme to the sata ssds, it stays at about 2 GB/s for the first five gigs or so and then falls off. Why is that? Shouldn't the nvme stay faster like it is in the benchmarks, even if its not quite as high?

[Archer42]

First of all - despite CDM popularity it is near-useless with modern SSD-s. Because SSD-s are fooling benchmarks like this with caches.

Second - speeds you see in specs are for caches. But samsung also publishes sustained speeds, unlike most manufacturers, in "datasheets". Write speeds are 600MB/s for 500GB 970evo and 500MB/s for 2TB 860evo (which will mean up to 1TB/s for 2*2TB 860evo in raid 0).

And then to complicate things a bit more windows also caches disk io in ram, so some of the speeds you are seeing are caused by those caching.

 

But then what you are seeing is strange. You cannot be getting 1TB/s sustained write onto 970evo, but you should be able to get it for the raid....

Are 860evo correctly correctly working in sata3 mode?