Kernel panic, can't find the reason.

[techo91]

Hi guys for the last week or so my home system is not stable and restarts by itself every day or two. I see a crash log when I enter the GUI. I'm attaching it to the post with the hope that someone can give me an idea what might be the issue.
This system was stable for more than a year before this. Old pc with three NIC's from which I'm using only two now.

I've tested the memory (4 plates of 512Mb) test is fine. This was my main suspect. I changed the thermal paste of the processor as well.

crash_report_pfsense.txt