So I have a NVME M.2 Samsung 960 EVO SSD, Samsung 840 EVO SSD and 2TB WD HDD. Windows is installed on the M.2. Every time I boot up all drives will show and I can access them but after 5 or so minutes the 840 EVO will drop out. It doesn't show in file explorer or disk manager after disappearing. I have to restart to get it back but it just drops out again. I have tried using different sata ports but it doesnt help. Funny thing is, if I install windows on the 840 EVO it works fine but the M.2 drops out. Any ideas? it has me buggered.