I had replaced by HDD on Alienware 15 R2 by Samsung 850 EVO and had MBR on that which was pointing to windows BOOT Samsung 951 NVME with SATA operation set to RAID. Everything worked perfectly. But this week I purchased Samsung 960 EVO and put it in place of Samsung 951 which had PCEI x4 interface and shifted 951 to vacant slot with x2 interface. Everything again worked fine.
But though I was getting recommended sequencial speeds 3100 MB/S and 1900 MB/S, IOPs were very low at about 120000. So I changed to safe mode in both Windows installations and changed SATA operation to AHCI and boot again. Thereafter problem started. Though boot order was 960 EVO and 951 NVME, it would show message of Checking media presence F1 to Reboot and F2 for Setup. If you press F1 it would go to 951 and not 960 EVO. But if your restart it would show dual boot options and allow to select 960 EVO as default option. If you select windows on 960 partition it would boot correctly and I would get 380000 IOPS. Secondly Samsung Magician could recognise hard disk and I could install Samsung NVME Driver which increased speed to 390000 IOPS.
So I boot from Windows 10 usb and selected repair option. First I corrected MBR with bootrec command. The problem did not solve. So I corrected UEFI.with bcdboot pointing to Windows installations on 960 EVO. Now I have funny problem. Whenever I power on my notebook it goes directly to 960 installation in few seconds (with secure UEFI boot option). But if I restart (from windows 10) it gives me checking media presence message after few seconds it states Press F1 to reboot, F2 to Setup... . If I press F1 it goes to 960 EVO installation. If I go for shutdown option from Windows and start with power button, everything works perfectly. But again if I restart from Windows problem repeats.
There is no other problem. Support Assist shows all test passing for all the 3 drives.But Samsung magician shows only 2 drives Samsung 850 EVO and Samsung 960 EVO. But windows disk partition as well as explorer shows all the 3 drives and all partitions work perfectly.
What is going on here. How I can correct this problem which is more of minor irritant.