The 965 X4 C3 ships in a slightly different and smaller retail box than previous processors, and the heatsink appears to be a new design as well; certainly much better than the unit that shipped with my 720 X3 BE! This one is similar in design to previous coolers packaged with AMD's Opteron chips, utilizing an aluminum thin-fin top soldered to a copper base with quad copper heatpipes, and includes an improved fan as well. It comes with thermal interface material already applied, although I will be putting the 965 under my Swiftech liquid-cooled system.
Here we see the "GM" indicated in the part number stamped on the IHS, indicating this is a C3 revision core. This particular chip is marked with an 0941 date which means it was manufactured sometime in mid-October. One difference between a C2 965 BE and the C3 is reduced voltage from 1.4v to 1.375v, which results in a 125W TDP rating instead of the older 140W of the C2. Stepped voltage is reduced from 1.025v down to 0.950v with Cool'n'Quiet enabled. The 3.4Ghz operating frequency remains the same.
Your motherboard may require an updated BIOS flash in order to recognize the new series. Some AM2+ boards may not support the latest AM3 chips at all. With AMD's six core Thuban planned for AM3 next year it looks like this socket interface will be around for awhile. At some point AMD will likely drop the DDR2 controller from new AM3 cores, with the costs of DDR3 and AM3 boards now below that of DDR2/AM2 hardware there really isn't much reason not to upgrade if you want to stay current.
Next let's look at overclocking.