"Although it can read data quickly, it is very slow at storing it.'"

That would read as a NOR flash problem.....fast read...slow write

NAND is the opposite....Slow read....fast write.

However, e.Digital scheme(cache) combined with it's data segment structure....IMO....improves with a fast read for Nand. Fast enough for them to deliver a  video and audio stream with quality.

They stream it directly off the flash through a small cache. This is not your typical shadowing or paging process.
doni