From a die standpoint a single 128 mb chip will always be more expensive than two 64mb chips. This is for two reasons. First of all, with a bigger the die size, more space is wasted fitting rectangular chips on a round wafer. Secondly a defect sufficient to ruin a die will ruin a larger piece if the die is larger. It is true that packaging is cheaper for a larger chip, and eventually the packaging savings offset the die size penalty, and therefore there always comes a time when the next generation chip is cheaper than the prior generation.
Samsung and NEC did not make an early transition to 128mb because the 128mb chip was cheaper to make than two 64mb chips. They made the switch because they believed it would be more profitable because they believed it would sell at a premium, and that premium would be larger than the extra cost to make the 128mb chip. Since it is not selling at a premium, I would say that they were wrong. But I predicted as much awhile back when so many people made the jump at one. I just don't think a half generation is enough to command a premium.
Usually DRAM makers jump 4x at a time, not 2x. Thus the normal next step up from 64mb would be to 256mb. I don't recall DRAM makers ever making volume parts at a half step before, so it is very unusual to see 128mb chips made in volume. I am assuming that one reason that the normal jump is 4x is that it is too expensive to keep starting a new generation every 9 months or so instead of every year and a half. Nevertheless NEC was getting kicked at 64mb, so they had to try something. Since the 128mb parts no longer sell for a premium, I'd have to say it didn't work.
My guess is that the 128mb chips don't have a very long life, and that makers quickly start ramping 256mb chips, again hoping for that elusive improved margins. I doubt that MU makes the move to 256mb before next spring, though they could if they wanted to. For them yield and volume are the approach, where others prefer to make the higher margin chips in smaller quantities. Once the costs of a 256mb chip reach the cost of a 4 64mb chips, look for MU to make the transition, but not before.
Good luck,
Carl |
