I have two of these in raid 0 in a Lenovo P70.

  fahad@heffalump:~/fiotest$  sudo fio --filename=$PWD/testfile --direct=1 --sync=1 --rw=read --bs=4k --numjobs=8 --iodepth=32 --runtime=60 --time_based --group_reporting --size=1G --name=journal-test
  journal-test: (g=0): rw=read, bs=4K-4K/4K-4K/4K-4K, ioengine=sync, iodepth=32
  ...
  fio-2.2.10
  Starting 8 processes
  journal-test: Laying out IO file(s) (1 file(s) / 1024MB)
  Jobs: 8 (f=8): [R(8)] [100.0% done] [367.8MB/0KB/0KB /s] [94.2K/0/0 iops] [eta 00m:00s]
  journal-test: (groupid=0, jobs=8): err= 0: pid=25184: Wed Jun  1 17:32:44 2016
    read : io=22265MB, bw=379986KB/s, iops=94996, runt= 60001msec
      clat (usec): min=15, max=19595, avg=83.59, stdev=102.01
       lat (usec): min=15, max=19595, avg=83.65, stdev=102.02
      clat percentiles (usec):
     |  1.00th=[   20],  5.00th=[   65], 10.00th=[   66], 20.00th=[   68],
       | 30.00th=[   75], 40.00th=[   79], 50.00th=[   80], 60.00th=[   82],
       | 70.00th=[   84], 80.00th=[   90], 90.00th=[   97], 95.00th=[  108],
       | 99.00th=[  141], 99.50th=[  173], 99.90th=[  900], 99.95th=[ 1704],
       | 99.99th=[ 4768]
      bw (KB  /s): min=43704, max=53976, per=12.51%, avg=47524.23, stdev=1225.35
      lat (usec) : 20=0.74%, 50=1.42%, 100=89.28%, 250=8.32%, 500=0.09%
      lat (usec) : 750=0.03%, 1000=0.03%
      lat (msec) : 2=0.06%, 4=0.02%, 10=0.01%, 20=0.01%
    cpu          : usr=1.38%, sys=7.92%, ctx=5737418, majf=0, minf=89
    IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
       submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
       complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
       issued    : total=r=5699889/w=0/d=0, short=r=0/w=0/d=0, drop=r=0/w=0/d=0
       latency   : target=0, window=0, percentile=100.00%, depth=32

  Run status group 0 (all jobs):
     READ: io=22265MB, aggrb=379986KB/s, minb=379986KB/s, maxb=379986KB/s, mint=60001msec, maxt=60001msec

That is awesome, what do you get with writes? (rw=write)

I ran both: https://gist.github.com/nlothian/e22ee30c6ccb8d473058d9e0864...

Read is a lot (LOT) faster than writes. Enough to make me thing I might have something misconfigurated there(?), although I'm not familiar enough with this benchmark to know for sure.

It's not unusual for write performance to be staggeringly worse than read on SSDs. It all depends how the controller is setup and how the manufacturer wants it to benchmark. Most sites emphasize read performance so the companies tune for it.

For 4K random reads, you'll probably want more than 32 iodepth, even on a consumer drive like this. And you'll want to try to write to each offset in the drive beforehand in case they have a "return 0" shortcut (like many enterprise drives).

Anandtech's results may be applicable here too: http://www.anandtech.com/show/9702/samsung-950-pro-ssd-revie...

Not in-front of it now. Will try to remember to do this though.

Please do this, the IOPS are very important!