In response to all the people asking how "deep sleep" works:

I have never used an NSpire, so I could be completely wrong. But I'm guessing "deep sleep" means writing the contents of RAM to flash, so the calculator can cut power to RAM. (Other calculators supply power to RAM all the time, since unlike flash memory it needs power to keep its contents.)

That's an interesting guess. I'm not a hardware expert, but I suppose that's a possibility. Maybe the Nspire has a different kind of RAM. Maybe it uses dynamic RAM rather than static RAM like the other calcs? I think dynamic RAM is cheaper but uses more power since it has to constantly be refreshed. But again, all this could be wrong.

Ok going on my memory of last semesters, "end of the semester chapter", but:

1. DRAM uses only 1 transistor "1-T Cell", so it's cheaper because you can put more memory on a chip making DRAM then static ram. So it's the area per chip that drives the price... or how many you can make per silicon wafer. And then when testing their will be some chips that are faulty, so that affects price to.

2. DRAM, besides needing a lot of refreshing because the capacitors leak, also has problem that reading data from a cell also destroys it, so all reads need to also refresh the contents of that cell.

3. Static ram... teacher said it's design dependent or something. Like the memory can be made by a bunch of 1-cell blocks, like a register... anyways we really didn't go over Static ram to much. But i think we learned you can read it without destroying it's contents.

Ok ya with SRAM it was not needing of refreshing like dynamic ram... just needs to be powered constantly.