Cooler, less likely to RRoD. It's all good, really.
Microsoft’s Xbox 360 trials and tribulations have been (s)fairly(/s) extremely well documented by now, although recently they seem to have been resolved – there’s certainly less news of consoles succumbing to the Red Ring of Death, anyway. That should be increasingly the case now as, confirming rumour from last October, the console’s GPU has also now been transitioned to a cooler, smaller 65nm manufacturing process.
The Jasper, as it is codenamed, platform should be found in Xbox 360s with a manufacturing date after the 6th of August this year and with a lot number of 8031 or higher. Don’t blame me if you get strange looks asking to look at all the Xbox packages in Game or Argos, trying to find such a unit.
As well as the obvious consumer benefits of a less power hungry and thus cooler, the transition also means better yields for Microsoft, and thus enhanced profitability from the console. Not that has anything to do with the recent price cuts we’re sure, though.
If you were for some (probably bizarre) reason, holding off buying an Xbox 360 until Jasper units were available then now’s your time. Everyone else, settle in for the real next big thing set to come to the Xbox community: Gears of War 2!