always wipe before install, i used to just set up windows, now I do clean on diskpart and that removes absolutely everything from a hard drive, even the GPT table gets wiped thing is never leave anything on your windows drive, whatever way delete everything on it, not just delete partitions and recreate them
Win 10 created 2 supplemental new partitions ??? i have no idea of their purposes ??? Win 8 or8.x had a 100 meg and a main partitions before. For a new install, i use a partition tool, always delete all partitions, ... boot from an dvd in uefi mode, no problems, i have a slic2.1 bios too