TYAN TOMCAT I7230B Manual page 41

As such, it would be a waste of L2 cache bandwidth to cache the video BIOS
instead of data that are more critical to the system's performance. In addition, if
any program writes into this memory area, it will result in a system crash. So, it
is recommended that you write protect this area for optimal system performance.
NULL / Write Protect
Cache Base 0-512K
This feature allows you to control caching of 512K base memory.
Uncached / Write Back / Write Through / Write Protect
Cache Base 512K-640K
This feature allows you to control caching of 512K 640K base memory.
Uncached / Write Back / Write Through / Write Protect
Cache Extended Memory Area
This feature allows you to control caching of system memory above one
megabyte.
Uncached / Write Back / Write Through / Write Protect
Cache A000-AFFF/B000-BFFF
These features allow you to control caching of A000-AFFF/B000-BFFF memory.
USMC Caching / Disabled / Write Through / Write Protect / Write Back
Cahe C8000-CBFF/Cache
D7FF/Cache D800-D8FF/Cahe DC00-DFFF
These feature allows you to control caching of C8000-CBFF/CC00-CFFF/D000-
D3FF/D400-D7FF/D800-D8FF/DC00-DFFF memory.
Disabled / Write Through / Write Protect / Write Back
CC00-CFFF/Cahe D000-D3FF/Cahe
41
http://www.tyan.com
D400-