3620 questions

HI all ...

Have a few questions on my 3620 precision tower Intel i7-6700.  If these have been answered previously, please let me know where the discussion is.

First question.  Can a person use both a video card (NVIDIA GeForce GT 710 in my case) and a port on the built in video adapter ?  have looked thru the bios and no luck so far.  was able to get it to work on a non-dell system a few years ago.  for work, I like to have 3 monitors for the office and 1 for my personal stuff.

Second question.  I've got a m.2 card that hosts my windows 10 C drive.  when I boot the system, it take a long time to come up, not something that happened when it had a standard HD on one of the SATA ports.  looking at the bios, it listed under the eufi config, "HD, 2, etc.).

what it seems is that it's trying to boot off of my data drive and only when it fails, does it go to the m.2 drive.  works fine when it starts up, so it's just a boot issue.  the system sees all the drive.

thus, can I revise the uefi to boot off of the m.2 first ?  looking online, I see comments about trying a different loader.  any thoughts / ideas would be greatly appreciated !!