I have just around to rebooting with the options applied. I have not tried them individually yet, but I did try with acpi=off and apic=off neither which helped. dmesg output with 'noapic pci=usepirqmask' applied to /boot/grub/menu.lst: #cat /var/log/dmesg MFACP 0x05000418 MSFT 0x00000097) @ 0x000000003ff30200 ACPI: MADT (v001 A M I OEMAPIC 0x05000418 MSFT 0x00000097) @ 0x000000003ff30390 ACPI: OEMB (v001 A M I OEMBIOS 0x05000418 MSFT 0x00000097) @ 0x000000003ff40040 ACPI: DSDT (v001 A0058 A0058002 0x00000002 MSFT 0x0100000d) @ 0x0000000000000000 ACPI: Local APIC address 0xfee00000 ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] enabled) Processor #0 15:14 APIC version 16 ACPI: Skipping IOAPIC probe due to 'noapic' option. Using ACPI for processor (LAPIC) configuration information Intel MultiProcessor Specification v1.4 Virtual Wire compatibility mode. OEM ID: ASUSTeK <6>Product ID: DELUXE <6>APIC at: 0xFEE00000 I/O APIC #2 Version 3 at 0xFEC00000. Processors: 1 Checking aperture... CPU 0: aperture @ f8000000 size 64 MB Built 1 zonelists Kernel command line: root=/dev/hda3 ro console=tty0 quiet splash noapic pci=usepirqmask Initializing CPU#0 PID hash table entries: 16 (order 4: 256 bytes) time.c: Using 1.193182 MHz PIT timer. time.c: Detected 2202.881 MHz processor. Console: colour VGA+ 80x25 Dentry cache hash table entries: 262144 (order: 9, 2097152 bytes) Inode-cache hash table entries: 131072 (order: 8, 1048576 bytes) Memory: 1022584k/1047744k available (1595k kernel code, 24420k reserved, 950k data, 124k init) Calibrating delay loop... 4308.99 BogoMIPS Security Scaffold v1.0.0 initialized Mount-cache hash table entries: 256 (order: 0, 4096 bytes) CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line) CPU: L2 Cache: 512K (64 bytes/line) CPU: AMD Athlon(tm) 64 Processor 3200+ stepping 00 ACPI: IRQ9 SCI: Edge set to Level Trigger. Using local APIC NMI watchdog using perfctr0 Using local APIC timer interrupts. Detected 12.516 MHz APIC timer. checking if image is initramfs...it isn't (ungzip failed); looks like an initrd NET: Registered protocol family 16 PCI: Using configuration type 1 mtrr: v2.0 (20020519) ACPI: Subsystem revision 20040816 ACPI: Interpreter enabled ACPI: Using PIC for interrupt routing ACPI: PCI Root Bridge [PCI0] (00:00) PCI: Probing PCI hardware (bus 00) ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT] ACPI: PCI Interrupt Link [LNKA] (IRQs 3 4 5 7 10 *11 14 15) ACPI: PCI Interrupt Link [LNKB] (IRQs 3 4 5 7 *10 11 14 15) ACPI: PCI Interrupt Link [LNKC] (IRQs 3 4 *5 7 10 11 14 15) ACPI: PCI Interrupt Link [LNKD] (IRQs 3 4 *5 7 10 11 14 15) ACPI: PCI Interrupt Link [LNKE] (IRQs 3 4 5 7 10 11 14 15) *0, disabled. ACPI: PCI Interrupt Link [LNKF] (IRQs 3 4 5 7 10 11 14 15) *0, disabled. ACPI: PCI Interrupt Link [LNKG] (IRQs 3 4 5 7 10 11 14 15) *0, disabled. ACPI: PCI Interrupt Link [LNKH] (IRQs 3 4 5 7 10 11 14 15) *0, disabled. usbcore: registered new driver usbfs usbcore: registered new driver hub PCI: Using ACPI for IRQ routing ACPI: PCI Interrupt Link [LNKA] enabled at IRQ 11 ACPI: PCI interrupt 0000:00:07.0[A] -> GSI 11 (level, low) -> IRQ 11 ACPI: PCI Interrupt Link [LNKB] enabled at IRQ 10 ACPI: PCI interrupt 0000:00:0a.0[A] -> GSI 10 (level, low) -> IRQ 10 ACPI: PCI interrupt 0000:00:0c.0[A] -> GSI 10 (level, low) -> IRQ 10 ACPI: PCI Interrupt Link [LNKC] enabled at IRQ 5 ACPI: PCI interrupt 0000:00:0d.0[A] -> GSI 5 (level, low) -> IRQ 5 ACPI: PCI Interrupt Link [LNKD] enabled at IRQ 5 ACPI: PCI interrupt 0000:00:0e.0[A] -> GSI 5 (level, low) -> IRQ 5 ACPI: PCI interrupt 0000:00:0e.1[A] -> GSI 5 (level, low) -> IRQ 5 ACPI: PCI interrupt 0000:00:0f.0[B] -> GSI 10 (level, low) -> IRQ 10 ACPI: PCI interrupt 0000:00:0f.1[A] -> GSI 11 (level, low) -> IRQ 11 ACPI: PCI interrupt 0000:00:10.0[A] -> GSI 11 (level, low) -> IRQ 11 ACPI: PCI interrupt 0000:00:10.1[A] -> GSI 11 (level, low) -> IRQ 11 ACPI: PCI interrupt 0000:00:10.2[B] -> GSI 10 (level, low) -> IRQ 10 ACPI: PCI interrupt 0000:00:10.3[B] -> GSI 10 (level, low) -> IRQ 10 ACPI: PCI interrupt 0000:00:10.4[C] -> GSI 5 (level, low) -> IRQ 5 ACPI: PCI interrupt 0000:00:11.5[C] -> GSI 5 (level, low) -> IRQ 5 ACPI: PCI interrupt 0000:01:00.0[A] -> GSI 11 (level, low) -> IRQ 11 agpgart: Detected AGP bridge 0 agpgart: Maximum main memory to use for agp memory: 941M agpgart: AGP aperture is 64M @ 0xf8000000 PCI-DMA: Disabling IOMMU. IA32 emulation $Id: sys_ia32.c,v 1.32 2002/03/24 13:02:28 ak Exp $ VFS: Disk quotas dquot_6.5.1 Dquot-cache hash table entries: 512 (order 0, 4096 bytes) devfs: 2004-01-31 Richard Gooch (