Intel® Architecture Instruction Set Extensions Programming Reference

Extracting the Maximum Processor Frequency from Brand Strings
APPLICATION PROGRAMMING MODEL
Table 2-30. Processor Brand String Returned with Pentium 4 Processor
EAX Input Value Return Values ASCII Equivalent
80000002H EAX = 20202020H
“ ”
EBX = 20202020H
“ ”
ECX = 20202020H
“ ”
EDX = 6E492020H
“nI ”
80000003H EAX = 286C6574H
“(let”
EBX = 50202952H
“P )R”
ECX = 69746E65H
“itne”
EDX = 52286D75H
“R(mu”
80000004H EAX = 20342029H
“ 4 )”
EBX = 20555043H
“ UPC”
ECX = 30303531H
“0051”
EDX = 007A484DH
“\0zHM”
Figure 2-6 provides an algorithm which software can use to extract the maximum processor operating frequency
from the processor brand string.
NOTE
When a frequency is given in a brand string, it is the maximum qualified frequency of the processor,
not the frequency at which the processor is currently running.
Ref. # 319433-014 2-47