What are you using the system for? If this is for gaming, I would take the 3300. For a workstation task, it is a little closer as the extra thread would be nice, but I would still probably get the 3300. You may have trouble finding a board for the x3440 and it is almost 10 years old. While there is only a 500mhz clock difference, the IPC and efficiency is much better on the 3300.