My servers are restarted. HELP

I have a strange issue with our servers. I use HP DL 360 for transcoding with ffmpeg and at least once a day they are restarted. We don’t find any errors or reasons for those restarts. Servers CPU’s are around 55% load with some peaks of 80-90% load. They are with CPU Intel Xeon X5650 2.67GHz. I tested with FreeBDS 10.2, 10.3 and 11 release and I compiled my own kernel with CPUTYPE? = nocona , but problem still appears.

Here are CPUs temperatures.
hw.acpi.thermal.tz0.temperature: 8.4C
dev.cpu.23.temperature: 59.0C
dev.cpu.22.temperature: 59.0C
dev.cpu.21.temperature: 61.0C
dev.cpu.20.temperature: 61.0C
dev.cpu.19.temperature: 59.0C
dev.cpu.18.temperature: 59.0C
dev.cpu.17.temperature: 61.0C
dev.cpu.16.temperature: 61.0C
dev.cpu.15.temperature: 55.0C
dev.cpu.14.temperature: 55.0C
dev.cpu.13.temperature: 61.0C
dev.cpu.12.temperature: 61.0C
dev.cpu.11.temperature: 58.0C
dev.cpu.10.temperature: 58.0C
dev.cpu.9.temperature: 58.0C
dev.cpu.8.temperature: 58.0C
dev.cpu.7.temperature: 60.0C
dev.cpu.6.temperature: 60.0C
dev.cpu.5.temperature: 60.0C
dev.cpu.4.temperature: 60.0C
dev.cpu.3.temperature: 61.0C
dev.cpu.2.temperature: 61.0C
dev.cpu.1.temperature: 61.0C
dev.cpu.0.temperature: 61.0C

Each server have 2 PSU in reserve - 750W instead 460W.
Please, give me advice how to find and fix the problem.
Kind regards
We have and Supermicro with CPU CPU: Intel(R) Xeon(R) CPU E5-2650 0 @ 2.00GHz (2000.05-MHz K8-class CPU) with FreeBSD 11.0-RELEASE and we have no issues, everything is fine.
Temperatures are high but this is to be expected when the CPUs have been pushed. They don't appear to be excessively high, I've seen CPUs with much, much higher temperatures.

I'd check for memory errors. That's probably the most likely cause. Also make sure the machine has all the latest firmware (BIOS, controllers, IPMI, etc).