I don't think it's a space issue; the 10,000 files only took up 27.3MB (as detailed
here). The processor is a bit pokey, but it shouldn't be that slow. My gut feeling is that the indexing system is written in Java, which is interpreted and can be slow, and it is more than likely sub-optimized for indexing a large number of books. Maybe subsequent updates will help. I'm certainly going to re-create this test on the iPad to see how it fares.
I saw the DVD set for every National Georgraphic at Costco for something like $69.00. It would be pretty cool to have all of that searchable. Although for now, PDFs are only searchable one at a time. See my latest article on Kindle search
here.