Looking at the firmware version, I' d strongly recommend upgrading. Patch 3 was one early version of the then brand new MR3 release, and if I remember correctly, MR3 was bug ridden at the beginning. No comparison to the current MR3 patch 15. I wouldn' t be too surprised if Fortinet had optimised for speed only in later patch releases.
"Kernel panic: Aiee, killing interrupt handler!"