Q: How's the IRQ sharing issue for BD7-II / BD7II-RAID motherboards?
A: AGP, PCI-1, PCI-2, PCI-3, PCI-4, PCI-5, PCI-6 dividedly used an IRQ.
Manually assigning the IRQs is possible in BIOS "PnP/PCI configuration" submenu,  
  1. PIRQ_0 is for AGP
  2. PIRQ_1 is for PCI-1
  3. PIRQ_2 is for HPT 372 Chip
  4. PIRQ_3 is for LAN
  5. PIRQ_4 is for PCI-2
  6. PIRQ_5 is for PCI-5
  7. PIRQ_6 is for PCI-4
  8. PIRQ_7 is for PCI-3

Notes:
Please be aware that BIOS function- "APIC" in "Advanced BIOS Features" and the default setting is "enabled". When APIC mode is enabled, there will be only three changeable IRQs for manually assigning PIRQ- IRQ 9, 10, and 11. For more information, refer to the following document please. http://www.microsoft.com/HWDEV/PLATFORM/proc/IO-APIC.asp