Recent Intel and AMD processors have an extend CPUID function call, that returns the name of the processor. In earlier cpu models you had to use the version and feature information function of CPUID to look up names in a string list of your own.

The function GetBrandString shows how to access the brand tring, provided the CPUID instuction is available.

function GetBrandString:string;
{Newer AMD (K5 Model 1/2/3,K6 Model 6/7, K6 -2 Model 8, K6-III Model 9,
   all Athlon and Duron) and Intel (Pentium IV) support a Processor Name String
   that is a 0 byte terminated string that can be a up to 47 characters long
   (terminating 0 byte excluded) terminating.
}  

function CPUIDAvail:boolean;assembler;
{Thests wheter the CPUID instruction is available}
asm
  pushfd             // get flags into ax
  pop   eax          // save a copy on the stack
  mov   edx,eax
  xor   eax, 0200000h    // flip bit 21
  push  eax          // load new value into flags
  popfd              // get them back
  pushfd
  pop   eax
  xor   eax,edx
  and   eax, 0200000h    // clear all but bit 21
  shr   eax, 21
end;
  
const
  CPUID=$a20f;
var
  s:array[0..48] of char;
begin
  fillchar(s,sizeof(s),0);
  if CPUIDAvail then begin
    asm
  //save regs  
       push ebx
       push ecx
       push edx
  //check if necessary extended CPUID calls are supported, if not return null string
       mov  eax,080000000h
       dw   CPUID
       cmp  eax,080000004h
       jb   @@endbrandstr
  //get first name part    
       mov  eax,080000002h
       dw   CPUID
       mov  longword(s[0]),eax
       mov  longword(s[4]),ebx
       mov  longword(s[8]),ecx
       mov  longword(s[12]),edx
  //get second name part    
       mov  eax,080000003h
       dw   CPUID
       mov  longword(s[16]),eax
       mov  longword(s[20]),ebx
       mov  longword(s[24]),ecx
       mov  longword(s[28]),edx
  //get third name part    
       mov  eax,080000004h
       dw   CPUID
       mov  longword(s[32]),eax
       mov  longword(s[36]),ebx
       mov  longword(s[40]),ecx
       mov  longword(s[44]),edx
  @@endbrandstr:    
  //restore regs
       pop  edx
       pop  ecx
       pop  ebx
     end;
   end;  
   result:=StrPas(s);
end;