Discussion in 'Article Discussion' started by Gareth Halfacree, 27 Sep 2013.
3D RAM to hit shop shelves soon.
If volume production is to start next year, why is it going to take three to five years for the first consumer products equipped with HMC RAM to appear on shop shelves?
Because that's how long it takes to design a product. HMC modules are not pin- nor electrically-compatible with existing DRAM modules, so to integrate them into your product means buying some samples, building prototypes, testing the prototypes, building more prototypes, testing those, repeating until they work, creating your design, testing your design, certifying your design, buying bulk units, producing your design and finally releasing your design. To put it another way: why haven't we got DDR4 in our PCs yet? The standard was finalised in September 2012, which was the originally-scheduled release-to-market date.
The other point to bear in mind is consumer products: I reckon we'll be seeing the first products with HMC by the end of 2014, but they won't be aimed at the consumer; they'll be niche products aimed at very specific markets and produced in very limited numbers. Much like multi-core processors once were...
Aha, now it makes sense. (I didn't realize they weren't compatible with current DRAM chips)
Another question: the sizes mentioned in the article are 2 and 4 gigabits or gigabytes per package?
Note the case of the "b"
Each HMC offers two gigabytes, made up of four layers of four-gigabit DRAM (4x4=16Gb, 16Gb/8=2GB.) The next step is the four gigabyte modules, although Micron hasn't stated whether these will be made by doubling up the layers (8x4=32Gb, 32Gb/8=4GB) or using higher-density layers (4x8=32Gb, 32GB/8=4GB.)
" using through-silicon vias (TSVs) to stack four 4Gb DRAM dies into a single 2GB cube." << Onto a single 2gb cube? Why not state the total capacity instead of saying "2gb". Last time I looked my 4 x mem modules came to 16gb = 4gb per module. Are they built on 2gb cubes too?
Take a look up-thread: I did state total capacity. A Gb is a gigabit, a GB is a gigabyte. There are eight gigabits in a gigabyte. The memory cube, as the article states, is made from four DRAM layers of 4Gb a piece; this makes for a cube of 16Gb capacity, or to use the more common measurement 2GB.
As for why the mixing of Gb and GB: the memory industry has always measured the chips themselves in Gb and the modules they make up in GB. That's just the way it works.
EDIT: Oh, and the 'gb' you talk about in your post? That's not a measurement of anything, I'm afraid. Case matters in this instance.
I wonder if these chips are going to be any bigger than current ones. I mean, they might be thicker, but are they going to need more PCB space also? With next year's 4GB packages, there could theoretically be 32 GB DIMMs with 8 (9 for ECC) HMC packages. That is, if they retain a comparable footprint.
I conclude that 'soon' means three to five years, therefore 'Later' probably means 10+ years and 'When I get around to it' is somewhere South of 2050.
Yes it is. a gb is a giga-bitch, which is a measure of whininess about things posted on the internets
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