X470 Taichi M2_2 slot spec?

you pretty much got it all wrong

x470 taichi m.2 doesn't change speeds when using 2 video cards


850 evo will only work on the first slot because that slot supports nvme(pcie) & sata interface m.2 drives. 850 are sata interface

you should only measure speeds with its raw performance not in any form of caching mode as you'll not always get those speeds all the time. 850 tops at 560MB/s sata limit. comparing with any pcie type its worlds apart already

Put it this way from my experience with a X470 Taichi Ultimate mobo and a 1TB Samsung 850 EVO m.2 ssd.
In m.2. slot 2 (bottom) = Unrecognized.
in m.2 slot 1 (top) It works perfectly fine.
Due to Samsung Magician's Rapid Mode, older drives can get well over 2000 mbps reads, so no real reason to need a newer model ssd to me.

Simply put, you are trying to use a SATA mode M.2 in an NVMe only M.2 slot

The M.2 interface can be annoying like that, you have to read the specs of your board to know which M.2 slot to use with what interface drive.

Edited by Xaltar - 07 Mar 2019 at 3:59pm

Hi,
My Ultimate SU800 128GB no recognized in m2_2 slot.
It only works fine in a M2_1.
But M2_1 can work with a Samsung EVO 970.
Can tell me why?