Why does Device Manager show 24 IRQs rather than 16 IRQs?
Gateway’s current motherboards include an Input Output Advanced Programmable Interrupt Controller (IOAPIC). IOAPICs were first used on multiprocessor computers to manage interrupt requests (IRQ) between multiple processors. IOAPICs have 24 IRQ lines. PCI 2.1 or later compliant device drivers allow PCI devices to share interrupt requests. There can be a performance bottleneck when multiple high performance devices are sharing the same IRQ. Using an IOAPIC on a single processor computer can improve computer performance. When multiple devices are on the same IRQ line, the interrupt controller must check each PCI device on that interrupt to determine which device initiated the IRQ. This process takes multiple PCI clock cycles. When the device that initiated the IRQ is found, the IRQ line stays active until the CPU satisfies the request. If two devices on the same IRQ line are both initiating IRQs at the same time, one of the devices has to wait until the other IRQ on the other IRQ line is
