Table 15. Effective Memory Type Based On Pat And - AMD Athlon Processor x86 Optimization Manual

22007E/0—November 1999
Page Attribute Table (PAT)
Table 15. Effective Memory Type Based on PAT and MTRRs
PAT Memory Type
UC-
WC
WT
WP
WB
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.
AMD Athlon™ Processor x86 Code Optimization
MTRR Memory Type
WB, WT, WP, WC
UC
x
WB, WT
UC
WC
WP
WB, WP
UC
WC, WT
WB
UC
WC
WT
WP
Effective Memory Type
UC-Page
UC-MTRR
WC
WT
UC
CD
CD
WP
UC-MTRR
CD
WB
UC
WC
WT
WP
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