14
Some expansion cards need an IRQ to operate. Generally, an IRQ must exclusively assign
to one use. In a standard design, there are 16 IRQs available but most of them are already in
use.
Standard Interrupt Assignments
IRQ Priority
Standard
function
0 N/A
System
Timer
1 N/A
Keyboard
Controller
2 N/A
Programmable
Interrupt
3 *
8
Communications Port (COM2)
4 *
9
Communications Port (COM1)
5 *
6
Sound Card (sometimes LPT2)
6 *
11
Floppy Disk Controller
7 *
7
Printer Port (LPT1)
8
N/A
System CMOS/Real Time Clock
9 *
10
ACPI Mode when enabled
10 *
3
IRQ Holder for PCI Steering
11 *
2
IRQ Holder for PCI Steering
12 *
4
PS/2 Compatible Mouse Port
13 N/A
Numeric
Data
Processor
14 *
5
Primary IDE Channel
15 *
1
Secondary IDE Channel
* These IRQs are usually available for ISA or PCI devices.
2-5-3 Interrupt Request Table For This Motherboard
Interrupt request are shared as shown the table below:
INT A INT B
INT C
INT D
INT E
INT F
INT G
INT H
Slot 1
√
Slot 2
√
Slot 3
√
Onboard USB 2
√
Onboard USB 3
√
HD Audio
√
IMPORTANT!
If using PCI cards on shared slots, make sure that the drivers support “Shared IRQ” or
that the cards don’t need IRQ assignments. Conflicts will arise between the two PCI
groups that will make the system unstable or cards inoperable.
2-5-4 PCI Express Slot
The motherboard series offer one 16-LANE PCI-Express x16 graphics slot of 4Gbyte/sec data
transfer rate at each relative direction which get 3.5 times of bandwidth more than AGP8X
and it’s up to a peak concurrent bandwidth of 8Gbyte/sec at full speed to guarantee the
performance and compatibility of GPU graphics add-in cards. The whole series carry three
32-bit PCI slots guarantee the rich connectivity for the I/O peripheral devices. One PCI
Express x1 I/O slots offer 512Mbyte/sec concurrently bandwidth which is over 3.5 times than
32-bit PCI at 133Mbye/sec.
