What is prefetchable and non-prefetchable memory? What is the difference between the two?
Prefetchable memory works by having blocks of memory copied out of the main memory into a small buffer controlled by the memory chipset. This makes repeated read operations from the same segment of memory faster. The buffer has to be flushed if a different segment of memory is read, of course, or if memory writes are being forcibly committed back to main memory, but it does speed read operations. Non-prefetchable memory does not use this mechanism; all reads and writes are done directly to memory.