I sure don't know the D3000 (never seen it, in fact) but I think you're on to something there. On the other hand, raw should have no noise reduction in any case (except long exp NR which I think you said you turned off). But there could also be other, completely non-obvious things, such as perhaps a requirement for images to be page aligned or something weird like that. Or perhaps the heap is allocated in that memory also, and depending on the routines in use it might grow to the point that it would limit the buffer - something that no user would ever know or care about in practice, but which limits implementation choices.
The other thing to consider is that the raw data in the buffer is not necessarily the size of the raw data we see written in a NEF file. (It might be, but I don't know where the buffer is in the pipeline.) Also, don't forget that these cameras compress raw files, and I'm almost certain that the raw files are far short of 16 MB in this state. (My D3 compressed raw files are usually 11-12MB.)
_____ Brian... a bicoastal Nikonian and Team Member
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