Techpowerup reports the "Jasper" revisions of the Xbox 360 console are showing up on retail shelves, these new models feature 65nm ATI GPUs and several other improvements which result in less power usage and lower heat levels. Hopefully this will mean the end of the Red Ring of Death.
The revised console comes bundled with a new 150W (12.1A whereas old model draw 14.2A) power supply that is 25W less powerful than the power supply bundled with previous generation Falcon consoles. The new power supply is almost 100% proof that the console you're looking is Jasper. Also, according to the report all consoles manufactured after October 23rd 2008 with LOT number 0843X and manufactured from FDOU, should be a Jasper. At last, let us remind what Jasper means. That's the official code name for the last generation Xbox 360 consoles.