Notes quoted from https://www.anandtech.com/show/556/9
PCI Slot IRQ-Sharing:
The CUBX features 6 PCI slots, but because the PIIX4e South Bridge only supports 5 PCI bus master devices, the sixth slot is a slave slot. At the same time, the fifth slot is also a slave since the CMD controller acts as a bus master PCI device, essentially leaving the CUBX with four PCI slots that you can populate with any PCI devices. The only types of cards that can work in a slave PCI slot are some PCI video cards, the Voodoo2 (since it doesn’t take an IRQ) and some network cards, so for most situations, those last two PCI slots are useless.
The CUBX’s IRQ sharing scheme is a little different than the rest of the boards since it has the 6 PCI slots and the on-board CMD controller. Again, the AGP slot can share an IRQ with either the first or the second PCI slots, the third and sixth PCI slots share an IRQ as do the fourth and fifth which also share an IRQ with the on-board USB controller. The on-board CMD controller shares an IRQ with the second slot.
DIP Switch or manual Frequency setting in BIOS ?
One of the most useful features of the JumperFree setup is that it will resort to a fail-safe setting of 66MHz x 4.0 for Pentium III Coppermine processors and 66MHz x 2.0 for all other CPUs and automatically take you to the Advanced settings menu of the BIOS and allow you to select your CPU frequency provided that the board doesn’t boot properly because of an incorrectly configured CPU (or if you overclock it too far). Just like the BF6/BE6-II, the CUBX features a set of 10 dip switches that can override the JumperFree setting, mainly for OEMs and system integrators that don’t want their users playing around with the settings unless they know what they’re doing