TAG MIL-BOOK 10 - Manual (Page 70)

Enables or disables the cache memory of your system: L1 cache (CPU
internal cache) and L2 cache (external cache). Cache memory enhances
system performance because the most frequently used data is accessed
from and written to the high-speed cache memory. For stable system
performance, you are not advised to change the default settings.
Resolution Expansion
Allows you to expand the LCD display.
Toggle XBay/EBox COM1/COM4 En/Dis
When this item enabled, COM1/COM4 on the X-Bay is enabled while
COM1/COM4 on the Expansion Box Port Replicator module is disabled.
When disabled, COM1/COM4 on the Expansion Box Port Replicator
module is enabled while COM1/COM4 on the X-Bay is disabled. A
check mark indicates enabled, while underline indicates disabled.
Setup Configuration Utility (SCU) 5-13