This post is actually for two questions. One is that my build is freezing and rebooting. I have checked the thermal paste and verified full coverage on the CPU. I have also run voltage checks on the PSU and all the voltages are on par.
The other issue that I have run into is that my PC will not boot when I connect the PCIe riser cable into Slot 2 on the motherboard. It will boot when I move the riser card to slot 4. Any assistance you can provide that will help resolve these two issues would be GREATLY appreciated.

Build is as follows:
Asus ROG Crosshair Hero VI BIOS 3502, will be updating to version 6201
AMD Ryzen 1700X
Corsair Vengeance LED DDR4 Memory 4x8GB 3200 MHz
ASUS ROG Strix GeForce® GTX 1070 Video Card
Samsung 960 EVO SSD 250GB M.2 Memory Card (Windows Boot Disk)
Samsung 850 EVO SSD Drive (Data Storage)
WD Blue SSD Drive (Data Storage)
2-WD NAS WD20EFRX-68EUZNO Drives in RAID1 Configuration (Back-up)
Noctua NH-D15 SE-AM4 Cooling Fan