make.conf AMD X2

[Benjamin Adams]

I was wondering what I should use in my make.conf for my processor:

CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ (2200.09-MHz
K8-class CPU)
  Origin = "AuthenticAMD"  Id = 0x20fb1  Stepping = 1

Features=0x178bfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,C
MOV,PAT,PSE36,CLFLUSH,MMX,FXSR,SSE,SSE2,HTT>
  Features2=0x1<SSE3>
  AMD Features=0xe2500800<SYSCALL,NX,MMX+,FFXSR,LM,3DNow+,3DNow>
  AMD Features2=0x3<LAHF,CMP>
  Cores per package: 2


Also after I change my make.conf will I have re-install all to take
advantage of this? (portupgrade -af)

Thanks

Benjamin Adams