Pegasus2 reading speed too slow, recurrent sleep problems

I have a pegasus2 R4 with 4 2TB hdd in RAID 5.

There were no problem using this product with my 2012 iMac. Recently I changed my 2012 iMac to 2017 iMac CTO (4.2 i7, 64GB ram, 1TB SSD)

After changing my system, pegasus2 shows 2 major problems.

1. Speed problem

Pegasus2 only shows write speed 300-400MB/s and read speed 150-200MB/s in blackmagic speed test. I connected pegasus2 via thunderbolt 3 to 2 adapter from apple. In iMac 2012 with thunderbolt 2 it showed write speed with 600-700MB/s, and read speed with 400-500MB/s. I updated my pegasus utility, firmware, and Mac OS driver with most recent ones, but it doesn't fix the problem.

2. Sleep problem

Pegasus2 sleeps after iMac sleep but automatically awakes after 1min (iMac is still in sleep). It keeps going to sleep and awake repeatedly all night long even if iMac is in sleep state. Also after this situation, if I awake the iMac, promise utilty won't work.

In the uploaded image, you can see the sleep and awake problem captured from promise utility.

I even made my enery saver from Mac OS, and uncheked the box "Put hard disks to sleep when possible", and also unchecked network awake & power nap activiation, but it still goes to sleep and automactically awakes.

I really want to know how to solve this 2 problems, because it's very annoying.

Any one else have similar problems?