Unable To Detect IRQ On A Video Blaster Card In A PCI System

Creative Video Blaster user may encounter the problem that their Video Blaster card could not detect an available IRQ when installing the card in a PCI based systems with Award BIOS V4.50G and SIS chipset. (BIOS code 4/06/95-SIS-501-503/2A5IAE41-00). This includes the following cards:

Video Blaster
Video Blaster SE
Video Blaster SE100
Video Blaster FS200
Video Blaster RT300
Video Blaster MP400

In most PCI based systems with Award BIOS V4.50G, the system will allocate available IRQs to the PCI bus first before allocating the rest to the ISA bus (eg. PCI bus has higher priority over ISA bus). In most cases the default IRQs allocated to the PCI bus are 10, 11, 9 & 12 in that order. While most of the Video Blaster cards are set at default IRQ 10, the Video Blaster software will fail to detect the IRQ setting when there is a PCI card installed in the system because IRQ 10 already been assign to the PCI slot.

Solution:

This problem can be solved by carring out the following procedures:

If you have only ONE PCI card installed in the system

This is normally the PCI VGA card in your system.

a. Go the the CMOS setup.

b. Select "PCI & Onboard I/O setup" option from the CMOS setup menu.

c. Change "1st Available IRQ" from "10" to "9" or "NA" ("NA" recommended).

d. Make sure that the rest of the "Available IRQ" options do not contain the same IRQ and they do not crash with other interface cards on the ISA.

If you have more than ONE PCI card installed in the system

This is normally the PCI VGA card and other I/O controller card (eg. PCI SCSI controller) in your system. Since you have more than one PCI card, you need to make sure that all the IRQ allocated to the PCI slots do not crash with each other and also other interface cards on the ISA bus. An easy way out is to change all the "Available IRQ" setting to "NA", however, some PCI cards that require IRQ may not function properly.

Note

As the root cause of this problem is in the way system/BIOS/chipset handles the IRQ request on ISA and PCI bus, it is therefore NOT an isolated problem on Creative products. In other words, any ISA interface cards that requires IRQ will have a potential problem with the PCI based motherboards with Award BIOS V4.50G, this includes any sound cards, video cards, I/O cards, VGA cards produced by other manufacturers.

Any ISA cards that have its setting at default IRQ 10 will have a higher possibilty of encountering this problem.