Here's what i figured to be more sensible:
Enable EFI boot (faster and sometimes more convenient than legacy BIOS boot):
If you don't need to use BIOS boot: Advanced → CSM Configuration → CSM Support: Disabled
If you do: Advanced → CSM Configuration → Boot option filter: UEFI and legacy
Enable ASPM on all ports (PCIe power saving): (viewtopic.php?f=80&t=128267&start=60#p837423)
Chipset → PCH-IO Configuration → PCI Express Configuration:
- For every PCI Express Root Port: ASPM: L0sL1; L1 Substates: L1.1 & L1.2
- For port 1, 2, 4 and 9: PCIE# CLKREQ Mapping Override: Custom number; CLKREQ Number: 0 for ports 1 & 2, 1 for 4, 4 for 9 (viewtopic.php?f=80&t=125573&start=90#p840308)
Please post anything else that you find useful.