Hi NightOwl; You're quite right. But power/heat generation depends strongly on how DRAM chips are used. All things being equal, I would think it would increase power by a significant amount, but they are also going to a more modern process, so that probably more than cancels the row size effect.
This is under the assumption (which I have not carefully examined), that they are in effect increasing their row size and decreasing the number of rows. This is just my first guess, I could be completely wrong here. It really doesn't matter, RDRAM is quite dead.
Generally speaking, power consumption is least when memories are organized to have more, but shorter, rows. The reason is that fewer memory cells (the tiny capacitors) have to be measured and then restored with each read or write cycle. Each access a DRAM has to write to many capacitors that were neither read by the memory controller nor written. The reason is that they have to read or write a whole row at a time. (Which is why they are called rows.) When the rows are longer, you get lots more power consumption.
This effect is most seen when comparing the power consumption of x4, x8, and x16 chips. While the individual memory chips have rows of the same length (for a given process type), the total number of bits in a "DIMM" row differ depending on the organization. It takes 16 x4 chips to make a row, but only 4 of the x16 chips. This means that a row of DIMM made from x4 chips uses 4x the power of a DIMM made from x16 chips.
-- Carl |
