The CPU Brand String is contained in the FriendlyName Value Name under a registry key similar to:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\ACPI\GenuineIntel_-_x86_Family_15_Model_\_0 Where _0 is the first CPU, _1 is the second CPU, etc..

Samples

On one of my laptops, FriendlyName at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\ACPI\GenuineIntel_-_x86_Family_6_Model_9\_0 contains Intel(R) Pentium(R) M processor 1700MHz.

On one of my desktops, FriendlyName contains Intel(R) Xeon(TM) CPU 2.66GHz at:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\ACPI\GenuineIntel_-_x86_Family_15_Model_2\_0                              HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\ACPI\GenuineIntel_-_x86_Family_15_Model_2\_1                              HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\ACPI\GenuineIntel_-_x86_Family_15_Model_2\_2                              HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\ACPI\GenuineIntel_-_x86_Family_15_Model_2\_3
I have scripted BrandString.bat to return all the FriendlyName data values.

The syntax for using BrandString.bat is:

BrandString VarName

Where VarName is a call directed environment variable that will be set as follows:

If CPU 0 cannot be found, VarName is set to NONE.
If CPU 0 is found, VarName is set to the number of CPUs and VarName0 is set to the CPU 0 FriendlyName.
If additional CPUs are found, VarName1, etc., is set to the appropriate FriendlyName.

BrandString.bat contains:
                              @echo off                              if \{%1\}==\{\} @echo Syntax: BrandString CPU&goto :EOF                              set $BrandStringVar=%1                              set %1=                              set $BrandStringkey=N                              for /f "Tokens=*" %%a in ('reg query "HKLM\SYSTEM\CurrentControlSet\Enum\ACPI" /S^|FIND "HKEY_LOCAL_MACHINE"^|Findstr /E /L /C:"\_0"') do (                               set $BrandStringkey="%%a"                              )                              If "%$BrandStringkey%" EQU "N" goto err                              set $BrandStringkey=%$BrandStringkey:\_0"="%                              set /a $BrandStringCPU=0                              for /f "Tokens=1,2*" %%a in ('reg query %$BrandStringkey% /S^|FIND "FriendlyName"^|FIND "REG_SZ"') do (                               set $BrandStringString=%%c                               call :parse                              )                              call set %$BrandStringVar%=%$BrandStringCPU%                              set $BrandStringCPU=                              set $BrandStringkey=                              set $BrandStringString=                              set $BrandStringVar=                              goto :EOF                              :err                              @echo Brandstring - CPUID NOT found.                              set $BrandStringkey=                              set $BrandStringVar=                              set %1=NONE                              goto :EOF                              :parse                              call set %$BrandStringVar%%$BrandStringCPU%=%$BrandStringString%                              set /a $BrandStringCPU=%$BrandStringCPU% + 1