This brings up another question. On my Athlon motherboard (DFI AK76-SN), all 
IRQs above 9 want to be shared, the BIOS simply wants them shared, and the 
CMOS config does not have means to disable IRQ sharing (there are plenty of 
spare IRQs below IRQ9). It was said Windows deals with this with ACPI by 
reassigning IRQs to devices after boot. It's possible the mobo manufacturer 
simply assumed all of us will be running Windows, and did not provide any 
configs in CMOS setup for dealing with shared IRQs. My older ASUS P5A 
motherboard never had IRQ sharing problems, and by default BIOS wasn't 
sharing them, in addition the CMOS setup had a configuration menu for per 
slot IRQ assignments. That said, does your motherboard share IRQs? If it 
does, that might as well be your answer, since sharing IRQs should lower 
performance.