The Cell microprocessor, jointly developed by IBM, Sony and Toshiba, that forms the heart of the Playstation 3 Slim is more powerful than the previous versions in the older, fatter, more finger-print friendly versions according to a spokesman for IBM.
PC World (the mag not, thank goodness, the retail chain) states, "The new chip has been manufactured using an advanced 45-nanometer manufacturing process, an IBM spokesman said. Based on IBM's Power architecture, the chip delivers many performance improvements while drawing less power than earlier chips, IBM has said. The earlier console carried a Cell processor manufactured using the 65-nm process. IBM declined to provide the clock speed of the new Cell processor."
So, younger, slimmer and now more powerful.