Samsung 990 pro 4TB nvme x2 TRAID system - slow write perf

[warlock00]

I have Samsung 990 pro 4TB nvme x2 set up as TRAID mirror.
Using as System drive and Volume1 with Apps.

Sequential Read is fine at 6800MB/s
But I am having unexpectedly very slow sequential write performance of 1900MB/s. Disappointed

Does anybody have any tips?
OR can someone running nvme in TRAID/mirror, provide me their write speed.
OR can someone running this Samsung nvme, not in TRAID, provide me their write speed. Maybe I will start fresh without TRAID.

fio --loops=5 --size=4G --ioengine=libaio --verify=0 --direct=1 --name=Seqwrite --bs=1m --rw=write --iodepth=64

Thank you

[Gremlin]

Which nas model? This can affect things due to the number/version of pcie lanes varies between models.

[warlock00]

And it helps if I mention important stuff like model.
F4-424 Max @ v 6.0.610
Less than 3 weeks old.
Both nvme slots and both nvme are Gen4x4. Chipset has max 20 pcie lanes.
I'm only using one 10GbE port at the moment.