Those who were expecting demonstrations of AMD quad core processors at CeBIT must have been quite pleased to see that not a single processor was in sight. Nevertheless, AMD spoke of the release of quad core processors: the Barcelona for servers scheduled to be released mid-2007 and the Agena for desktop which will be available in September.
We were unable, however, to find other information than the official ones and the processor frequencies, 2.1 to 2.3 GHz for the Barcelona and 2.4 to 2.6 GHz for the Agena, haven't been confirmed. Also, if no specific indications were given about the desktop performances, AMD speaks, of course, of higher performances than Intel's products.
The good news is the compatibility of AM2+ quad core processors with current AM2 motherboards. Indeed, according to AMD but also a well known motherboard manufacturer, this compatibility will be effective.
A motherboard with an AM2 socket will be compatible with AM2 and AM2+ CPU and vice versa. Also, according to the same manufacturer, future AM3 processors using 45nm fabrication process and compatible with DDR2 and DDR3 will be compatible with current motherboards. AM2 and AM2+ processors will not, however, be compatible with AM3 motherboards as the latter is restricted to DDR3. Of course, with AM2 sockets, future AM2+ quad core processors will not express their full potential: they will not work with HyperTransport 3.0 but with 1.0, and the distinct voltage between the cores and the memory controller will not be possible.
There is one question left: under those circumstances why AMD doesn't communicate more on the upgrade possibilities?