I actually only added them recently. I felt that people would not take my advice seriously with system specs like that! My son has an i5-650 based system and my girls use a PII 805 system, so I'm not totally out of date. Things have changed. Your 930 will no longer do -bigadv. You need 16 threads for -bigadv. Electrically wise, best to idle the CPU's as Stanford has greatly reduced the PPD for SMP to 1/4 to 1/3 of what it used to be. The good news is that GPU's are getting more. GTX 460's used to be ~10-11K PPD and now they get 16-20K PPD.