user manual

Page Attribute Table (PAT) 179
22007E/0—November 1999 AMD Athlon™ Processor x86 Code Optimization
Table 15. Effective Memory Type Based on PAT and MTRRs
PAT Memory Type MTRR Memory Type Effective Memory Type
UC- WB, WT, WP, WC UC-Page
UC UC-MTRR
WC x WC
WT WB, WT WT
UC UC
WC CD
WP CD
WP WB, WP WP
UC UC-MTRR
WC, WT CD
WB WB WB
UC UC
WC WC
WT WT
WP WP
Notes:
1. UC-MTRR indicates that the UC attribute came from the MTRRs and that the processor caches
should not be probed for performance reasons.
2. UC-Page indicates that the UC attribute came from the page tables and that the processor
caches must be probed due to page aliasing.
3. All reserved combinations default to CD.