I have a combination of the following hardware: Corsair RM-550 PSU, MSI X99S SLI motherboard, MSI 2GB D5 X GTX960 graphics and a Intel 400GB 750 Series (PCIe card). I'm booting from another Samsung 850 Pro SSD over SATA.
When the PC is on, everything is fine and I can restart the PC without problems. If I shutdown the PC, turn it to sleep or unplug the power cable, my PC will boot to Windows but won't see Intel 750 SSD (I can see it graphically in the BIOS as not detected). Only when I unplug the PCIe card physically from the PCIe slot (while power off) and plug it in a second later, the motherboard detects the card again. Also when I leave the PC unplugged to power for a few hours, the SSD gets recognized again. I tried all PCIe slots.
I updated BIOS and SSD firmware, I have a motherboard that supports the NVMe protocol. It searched a long time before and can't find any info other than potentially issues with the capacitors on the motherboard or PSU (Why does my PC successfully boot only when unplugged for more than a few minutes?)
What do you guys think? Motherboard, PSU or SSD issue?