Intel® Architecture Instruction Set Extensions Programming Reference

APPLICATION PROGRAMMING MODEL
The Processor Brand Index Method
Figure 2-6. Algorithm for Extracting Maximum Processor Frequency
The brand index method (introduced with Pentium ® III Xeon ® processors) provides an entry point into a brand
identification table that is maintained in memory by system software and is accessible from system- and user-level
code. In this table, each brand index is associate with an ASCII brand identification string that identifies the official
Intel family and model number of a processor.
When CPUID executes with EAX set to 1, the processor returns a brand index to the low byte in EBX. Software can
then use this index to locate the brand identification string for the processor in the brand identification table. The
first entry (brand index 0) in this table is reserved, allowing for backward compatibility with processors that do not
support the brand identification feature. Starting with processor signature family ID = 0FH, model = 03H, brand
index method is no longer supported. Use brand string method instead.
Table 2-31 shows brand indices that have identification strings associated with them.
2-48 Ref. # 319433-014