I am buying a sTRX4 motherboard for the 3960x threadripper. I need roughly 140 gb of ram for my tasks. What is the optimal way to set this up RAM wise? Must I use all 8 slots at 32gb for 258gb total? Or can I use 5 or 6 of the slots to save some money? I am assuming I also cant mix and max 32gb/16gb sticks without compromising performance as well.