I checked the documentation for the 2 primary competitors of the Intel WX58BP. They are the Asus P6T6 WS and the SuperMicro X8STI. Like the WX58BP, both competitors use the x58 chipset, but unlike the WX58BP, both competitors have documentation that clearly explains all the options in each screen of the BIOS setup.
Both competitors allow enabling the following number of cores in a 4-core processor.
Why does Intel refuse to document this information for the WX58BP?