LSI 9200-8e, DS4246, SSD Speeds and ses: transfer speeds

I'm running some tests on different configurations and am puzzled by some of the results I am getting.

My setup:
IBM x3650 m3 , 2 x5650 cpu, 128GB ram
LSI 9200-8e
2 x Netapp DS4246 with IOM6 (6 gbps)
8 x 4TB Seagate iron wolf in raidz2 sata
1 x samsung evo 850 120GB in stripe sata
Freenas 11.1-U6

test6.out = 42GB file generated with dd if=/dev/random, file is on th 8x4TB raidz2

/mnt/ssd=ssd stripe of samsung 850 evo 120GB

dd if=./test6.out of=/mnt/ssd/test1.dd bs=1024K

If I...

LSI 9200-8e, DS4246, SSD Speeds and ses: transfer speeds