I am hacking layman ( and thus far from being an expert on the matter), but it seems to me as a bad idea, at least with current generations of HW and SW.
Encryption is by nature very serial. You do transformation X on some block of data and it has to be completed before you can begin with transformation Y. If there were significant shortcuts, they would mean that crypto is weak. Crypto is all about transforming the data in non-obvious way, after all...