Sometimes, stocks go down for pretty stupid reasons, and we may have one of those situations today with SanDisk (NASDAQ:SNDK).

The stock dropped as much a 6% earlier today, apparently owed to the news that Freescale Semiconductor (NYSE:FSL) is first to market with the Holy Grail of nonvolatile memory: magnetoresistive random access memory, or MRAM.

MRAM is like flash memory, in that it hangs onto data when the power's off. But it's also like the RAM in your computer, in that it's blazing fast (even faster than DRAM) and lasts a long, long time.

But it's unlike both of those in its lackluster capacities -- which investors need to keep in mind.

Freescale's current MRAM product has a capacity of 4 megabits. Unless my math is wrong -- and in the geeky world of bits, bytes, and such, it's possible -- Freescale's RAM killer sports a whopping 0.48 megabytes, at a cost of $25 per chip. For comparison, according to recent spot-market prices sent to me by a flash-market watcher, $31 gets you a flash memory chip of 1,907 megabytes.

That means you won't be seeing Apple (NASDAQ:AAPL) filling up the iPod nano with MRAM any time soon, and it's why SanDisk, with partner Toshiba, doesn't have much immediate reason to fear MRAM, either. The same goes for the flash-memory partnership between Intel (NASDAQ:INTC) and Micron (NYSE:MU), which was jumpstarted by Apple's cash. Flash is generations ahead and will see increasing demand, which is why these firms, along with world flash production leader Samsung, continue to invest so heavily in capacity.

Freescale, of course, would like us to believe that the tech folktale of periodic doubling will soon bring MRAM capacities into line with established storage media. Unfortunately for them, flash producers, not to mention hard drive makers like Seagate (NYSE:STX), aren't exactly standing still. Their capacities will also swell. It will be a very long time before we see the future that MRAM proponents have long predicted -- a world where MRAM technology would replace everything.

Certainly, Freescale investors might see some benefits should the product find its way into the niches where it's useful -- cars, small tech devices that need ultra-fast, stable memory -- but a sea change in the storage industry, this is not. Invest accordingly.

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Seth Jayson thinks there might be plenty of good reasons to sell SanDisk, but this isn't one of them. At the time of publication, he had shares of SanDisk, but no positions in any other company mentioned. View his stock holdings and Fool profile here. Intel is a Motley Fool Inside Value recommendation. Fool rules are here.