FUD Zilla reports AMD is prepping to introduce a new Sempron chip in Q4 2010:
The new Sempron scheduled to launch in Q4 2010 is AMD Sempron 150 and works at 2.9GHz. It has a 45nm single core and 1MB of cache memory.
Sargas generally supports DDR3 1066 and it likes AM3 boards and sockets. This CPU will top the currently available Sempron 140 that works 200MHz slower. There should also be a Sempron 145 that works at 2.8GHz but it's not available at this time, but it should be soon.
Sempron single core at 45nm should live at least trought the first part of 2011.