In short it’s because the BIOS routes IRQ lines incorrectly in IO-APIC mode. Disable IO-APIC mode if you want to use the onboard USB on a PR440FX motherboard.
See the following links.
Archive for December, 2013
Why does USB lock up my system with the Intel Providence PR440FX motherboard?
Tuesday, December 10th, 2013Matrox G200 (SE) in SR2600 server fails to start X server on CentOS 5
Tuesday, December 10th, 2013On CentOS 5 (and possibly the corresponding RHEL), the Matrox G200 driver fails when using an embedded G200SE on a SR2600 server. If you run the X server under gdb or look at the last lines of the Xorg.0.log output, you can see that the X server stopped loading due to the mga_drv.so driver module producing a segmentation fault. The segmentation fault is due to incorrect probing of the available memory size.