F5-420 Raid 5 HDD 1 Failed after restart and everything is gone

[Benini]

After the engineer has checked my nas over putty, we reinitialized the nas and he checked / created some files.
So now, after 200GB and more transfere and tos update, all is working well and i can restart my nas without reinitialisation.

Last question:
is it possible that my raid 5 with 5x2tb wd 2003fyys enterprise storage and XOR Link Aggregation have a performance of:
105 Mbyte/s write
80 Mbyte/s read speed
?
(tested with NAS tester 1.7, 5 iterations 400mb file, over networkpath "\\TNAS-006FF7\public")

Thanks