HP has accidentally leaked three AMD A-series APUs while updating the service guide for HP Pavilion g7. The update simply includes SKUs and specs for three yet to be released APUs, which suggests that HP will be utilizing these APUs in Pavilion g7 at some point. All three are mobile variants like the M at the end suggests. Below is a table of AMD's A-series mobile lineup - the unreleased CPUs are in bold.

Some of the specs have a (?) after them because those specs were not found in the HP datasheet, but they are our guesses based on the other models of that family. All in all, it looks like A8-3520M will be A8-3500M with 100MHz higher clock speed and Turbo, A6-3420M is A6-3400M with 100MHz higher Turbo and A4-3320M is A4-3300M with 100MHz higher clock speed and Turbo. Increasing the frequency multiplier by one is a pretty common way of delivering smaller updates between bigger updates like die shrinks and micro-architecture changes, so this is nothing special. 

Source: HP