ACPI (power management) has been known to cause problems on some Windows machines, with USB dropouts on powerful CPUs.
If you have USB dropouts and are having trouble finding a cause on a seemingly powerful machine, check if your computer is ACPI by opening the device manager:
- Go to control panel
- Click system
- Click the hardware tab
- Click device manager
- Click the [+] next to Computer
- If you see "ACPI uniprocessor PC" or similar, you have ACPI.
Quick method for disabling ACPI power management on some laptops running Windows XP or Windows Vista.
Try taking your battery out and just run off the power supply, this stops ACPI from trying to manage the battery on some model laptops.
You can disable ACPI if you think it might still be a problem:
HOWEVER IT CAN BE HARD TO REVERSE THIS, AND YOU MAY HAVE IRQ CONFLICT ERRORS, SO DON'T DO THIS UNLESS YOU KNOW WHAT YOU'RE DOING AND CAN AFFORD SOME SYSTEM DOWN-TIME! AND MAKE A BACKUP!
BEFORE PROCEEDING Make a new system restore point by using the system restore wizard in help and support (start menu).
"If you right-click on the 'Advanced Configuration and Power Interface (ACPI) PC' description and select the Properties option, and then the Driver page on the window that appears, you can select 'Update Driver'. Choose the second 'Install from a list or specific location (Advanced)' option on the subsequent page, and then the 'Don't search. I will choose the driver to install' option on the following page. This should come up with two options, namely ACPI PC and Standard PC." (from www.soundonsound.com)