No, those newthat were released last weekend do not contain the new 65nm chips that Microsoft promised us. Production on those new silicon wafers is only starting this month, so they won't be finding their way into consoles you can actually buy until the fall.
For those keeping score, that means the new 65nm technology will be incorporated into both the game machine's CPU (central processing unit) and GPU (the dedicated graphics chip). The new smaller chips reportedly run a lot more efficiently than those found in current Xbox 360s. That should mean less power consumption, a cooler running temperature, and--since cooling fans won't have to work overtime--the possibility of a quieter overall system.
[Source: Commercial Times (China) via Kotaku.]