I'm about ready to pull the trigger on purchasing it, but I can't find any info on the PCIE lane sharing. I know that M.2_1 is Gen4x4 to the CPU and M.2_2 is Gen3x4 to the chipset. However, there's no info in the manual or anywhere else I could find on what happens if you populate both. I don't mind giving up a SATA slot, but I sure don't want to see the GPU suddenly drop from x16 to x8. Also, I couldn't find out whether both slots are bootable or just M.2_1. Thanks!