The major change in Phenom II is that it is built using a 45nm immersion lithography manufacturing process which, "enables higher frequencies, tighter tolerances and lower current leakage." The other major change is the L3 cache which is now three times as large at 6MB over 2MB of Phenom and the L3 cache is also 2-cycles faster. There are a number of other improvements as well, ACC (Advanced Clock Calibration) is now apparently baked into the silicon so a SB750 chipset is not required to get more overclocking headroom out of the Phenom II. Another thing to note is the HT bus on these new processors runs at 1.8GHz instead of 2GHz of the 9950 due to a trade off in priorities to get the chip ready to market. The bus isn't even close to being saturated with anything but servers so this isn't a major loss.



Link: AMDZone