Our test procedure starts out with a light conditioning phase, so our numbers do not always correlate with what the vendors claim in their marketing material. Specifications printed on retail packaging and webpages are sometimes called hero numbers, since the performance is measured at the best possible time, when the drive is fresh out of its box.
The three JMicron JMF670H-based products group together in the sequential read test. At first, we were surprised to see the 256GB model outperforming the 480GB version with Toshiba 15nm flash. It's possible that the lower-power M.2 interface plays some role in these results, though. This is the first time we've tested production Toshiba 15nm.
Still, as it sits in its current form, the JMF670H with L95B NAND is a bit slower at sequential reads than Phison's S8 with the same flash (as benchmarked on Patriot's Torch 240GB).