Many systems have shared interrupts between the USB controller and other components. In order to reduce any performance impact due to the shared interrupts, we can configure the ESX to avoid loading the USB drivers.This VMware KB 1290 has more detail information
- Configure the USB controller setting in BIOS to enable USB, so that the system supports USB devices both during and after ESX boot process even if USB drivers are not loaded by the ESX software.
- Remove the following USB modules aliases from /etc/modules.conf
- Save /etc/modules.conf and restart the system
alias usb-controller usb-uhci
alias usb-controller1 ehci-hcd
on how you can tell if your system has shared interrupts.