I am looking at buying the opty 170 but after looking at the specs for both processors stated above. I can get the 4400 for just a little more. I know that the opty will overclock better but I only plan on oc'ing 200-300mhz anyway. The 4400 has 128k L1 cache vs 64k in the opty and the 4400 is 200mhz higher clock speed to start with.