Is there a significant difference in performance between low-level datastore API and JDO/JPA?

Should I expect a noticeable performance boost after switching from JDO/JPA to low开发者_C百科-level datastore API? Also, are there any things I should be aware of before switching?

The difference is small, and seem to vary more based on the load on the google servers than the API used.

You can view a realtime test yourself here: http://gaejava.appspot.com/

No - they all use the same underlying RPCs, so they will all have more or less equivalent performance. You certainly shouldn't change your interface of choice based on performance concerns.