I just upgraded my cpu from 3930k to 4930k on a Rampage IV Extreme. Upon getting the system running again, I have at least 20 "Base System Devices" under Other Devices, with a yellow question mark. I have installed all the Asus drivers again, but the items still remain. Could someone tell me where these came from and how to resolve them.

If you get a yellow exclamation mark for certain devices in the Device manager, most probably the device driver is corrupt or configured incorrectly. “Base system devices” as the name suggests are some basic essential devices in the computer. If a proper device driver was not installed, Windows will just display the default category name that is “Base system device”. In this case, I would suggest you to try these steps and check:

First, I would suggest you to check the device status to confirm if this is a driver issue or a hardware issue. Refer to these steps to check the device status:

Press Windows key + X, select Device manager.
Locate the device.
Right click on the device and select properties.
In the General tab, check the device status.

Method 1:
I would suggest you run the Windows update, so that it can check and install any drivers available for the device. Refer to the section “Do I need to check for updates” section in this article:

http://windows.microsoft.com/en-in/windows-8/windows-update-faq

Method 2:
If there were no updates available or if the issue persists even after checking for updates, then I would suggest you to check the for the hardware ID so that we can determine what device it is and get the appropriate driver for the update. Open device manager as suggested above and right click to get the “properties” window. Click on “Details” tab and under property, choose “Hardware ID” make a note of it.