Max CPUID Value Limit: This is mainly used for Intel Pentium 4 processors with HyperThreading technology. It allows higher level CPU ID values to be used like 03h (hexadecimal values). This only needs to be enabled if the operating system does not support specific features. Note: For all later versions of windows this does not need to be activated, same with most Linux distributions. Just so you know what it does, CPUID as the name suggests gets information about the processor, the higher the value it supports the more information is able to be obtained.
Vid CMOS settings: This one I am not to sure about, what I believe is that this allows you to set the "vid settings" which the CPU is to run. Any other better or more expanded definitions would be appretiated by other members.