If MS switches to GDDR5 now, did Sony make a silly mistake?

[Kynes]

Why? There is something that most people seem to forget, right now there aren't on the market 4 Gb GDDR5 chips, so Sony will have to use 16 chips of a new type of chip and package on package, which isn't cheap at all, and could provide some yields problems. MS seems to have taken a cheaper route, mass market memory with the embedded memory on chip, a much cheaper solution.

The Sony solution has more grunt, but it smells PS3 all over again on the cost department.