Common Options : 1.1, 1.4
This feature is only applicable to multiprocessor motherboards as it specifies the version of the Multi-Processor Specification (MPS) that the motherboard will use. The MPS is a specification by which PC manufacturers design and build Intel architecture systems with two or more processors.
MPS 1.1 was the original specification. MPS version 1.4 adds extended configuration tables for improved support of multiple PCI bus configurations and greater expandability in the future. In addition, MPS 1.4 introduces support for a secondary PCI bus without requiring a PCI bridge.
If your operating system comes with support for MPS 1.4, you should change the setting from the default of 1.1 to 1.4. You also need to enable MPS 1.4 support if you need to make use of the secondary PCI bus on a motherboard that doesn't come with a PCI bridge.
You should only leave it as 1.1 only if you are running an older operating system that only supports MPS 1.1.
According to Eugene Tan, Windows NT already supports MPS 1.4. Therefore, newer operating systems like Windows 2000 and Windows XP shouldn't have any problem supporting MPS 1.4.
However, users of the ABIT BP6 motherboard and Windows 2000 should take note of a possible problem with the MPS version set to 1.4. Dan Isaacs reported that when you set the MPS version to 1.4 in the ABIT BP6, Windows 2000 will not use the second processor. So, if you encounter this problem, set the MPS Revision to 1.1.