How to diagnose random reboots on AMD/Linux

Hi, ever since I got my new build, I have been experiencing random reboots, I would like to find out what’s been causing this.

My system info:

inxi -Fz
System:    Host: primary Kernel: 4.12.7-1-MANJARO x86_64 (64 bit)
           Desktop: Cinnamon 3.4.4  Distro: Manjaro Linux
Machine:   Device: desktop Mobo: Micro-Star model: B350 TOMAHAWK (MS-7A34) v: 1.0
           UEFI: American Megatrends v: 1.60 date: 06/22/2017
CPU:       Octa core AMD Ryzen 7 1700X Eight-Core (-HT-MCP-) cache: 4096 KB 
           clock speeds: max: 3400 MHz 1: 2200 MHz 2: 2200 MHz 3: 2200 MHz
           4: 2200 MHz 5: 2200 MHz 6: 2200 MHz 7: 2200 MHz 8: 2200 MHz
           9: 2200 MHz 10: 2200 MHz 11: 2200 MHz 12: 2200 MHz 13: 2200 MHz
           14: 2200 MHz 15: 2200 MHz 16: 2200 MHz
Graphics:  Card: Advanced Micro Devices [AMD/ATI] Ellesmere [Radeon RX 470/480/570/580]
           Display Server: x11 (X.Org 1.19.3) drivers: amdgpu (unloaded: modesetting)
           Resolution: [email protected]
           OpenGL: renderer: Gallium 0.4 on AMD POLARIS10 (DRM 3.15.0 / 4.12.7-1-MANJARO, LLVM 4.0.1)
           version: 4.5 Mesa 17.1.6
Audio:     Card-1 Advanced Micro Devices [AMD] Device 1457
           driver: snd_hda_intel
           Card-2 Advanced Micro Devices [AMD/ATI] Device aaf0
           driver: snd_hda_intel
           Sound: Advanced Linux Sound Architecture v: k4.12.7-1-MANJARO
Network:   Card-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
           driver: r8168
           IF: enp33s0 state: down mac: <filter>
           Card-2: Realtek RTL8188EUS 802.11n Wireless Network Adapter
           IF: N/A state: N/A mac: N/A
Drives:    HDD Total Size: 2128.4GB (35.3% used)
           ID-1: /dev/sda model: KINGSTON_SUV400S size: 120.0GB
           ID-2: USB /dev/sdb model: My_Book_1230 size: 2000.4GB
           ID-3: USB /dev/sdc model: USB_Flash_Drive size: 8.0GB
Partition: ID-1: / size: 101G used: 18G (19%) fs: ext4 dev: /dev/sda2
           ID-2: swap-1 size: 9.45GB used: 0.00GB (0%) fs: swap dev: /dev/sda3
Sensors:   System Temperatures: cpu: No active sensors found. Have you configured your sensors yet? mobo: N/A gpu: 29.0
Info:      Processes: 303 Uptime: 2:18 Memory: 3429.1/8003.2MB
           Client: Shell (fish) inxi: 2.3.27

/var/log/syslog and /var/log/kern would be helpful? lsmod and modinfo on anything related to your graphic card would be helpful as well.

Bios update/rollback available? Not all Ryzen platform bios’es work that well out of the box