
Actually over 100x more dense
Feature size on a chip scales via square (i.e., you get 4x more transistors on a 45 nm chip than on a 90 nm chip, all else being equal) So its more like 100-400x as dense, not 10-20x.
However, I assume they are talking about the minimum size it could scale to, not the size of the first generation product. Either way, I'm sure a lot of development would be required to mass produce it. IBM's MRAM has been 'a few years away' for years now, it is starting to remind me of bubble memory, the next big thing back in the 80s. Hopefully this technology will not suffer the same fate, but time will tell.