After issue #4759 has been fixed, I suspect a new memory leak:
reports “istgt” as most memory consuming process. Is this worth submitting a bug report? As far as I understand “istgt” is being phased out in the upcoming releases in favour of another implementation.
FreeNAS-9.2.1.4.1-RELEASE-x64
G2020, 32GiB ECC

Code:
top -o size
FreeNAS-9.2.1.4.1-RELEASE-x64
G2020, 32GiB ECC