Does anyone know the maximum size of content that I can send through the broadcast?
I expect that you will begin to encounter problems around the 1MB label for the entire shared Intent , as there are restrictions on the Binder based IPC that underlies the Intent system.
How does data size affect device performance?
Since Intent objects are copied between processes as a result of broadcasts, you will consume enough RAM during translation, plus enough processor time to copy memory between processes.
I would agree with rciovati's comment: "IHMO several kb are" huge "for going through with Intent."