I'm in the process of acquiring my parts (the Rampage V Extreme x99 being the last major item I'm still tracking down for purchase) and want to ensure maximum throughput as well as the best options for multi-boot, potentially with Linux and/or OSX.

Questions:
1. UEFI will generally offer the best boot and speed benefits in conjunction with a windows 8.1+ installation, correct? If so, do I select this during Windows' fresh install or is it selected and configured on the drive in advance? I know it would need to be enabled/disabled in the BIOS should conversion from an existing MBR-based boot disc be utilized.

I currently have a Crucial M500 960GB SSD which was my prior Win 7 MBR disc with boot/os/game partitions. I'm looking to repurpose that drive for use as either a primary for OS or secondary for steam/origin gaming. This leads to my subsequent questions:
2. Do I convert that to UEFI (with something like http://social.technet.microsoft.com/wiki/contents/articles/14286.converting-windows-bios-installatio...) only if it's a primary or does it also need to be converted for maximum performance even if a secondary?
3. If it is the primary and is RAID 0 does it need UEFI if it is the second drive of a raided pair or does that only go on the first drive of a raided pair or get striped across both volumes once? I'm assuming it would be striped across both in that scenario.