PRAM, MRAM, NRAM

[Cogman]

I was just reading some wikipedia articals on future Nvram technologies, and I must say some of them look very impressive. I think that it is only a matter of time before somebody decides to invest in them and can see some great benifites for it.

So What do you guys think about them? Which do you think has the brightest future, and which is the dimmest?

From what I have read so far, I think that NRAM probibly has the brightest future because it can be the most dense. MRAM looks really good as well to me. Its really exciting to think that they could put a couple of NRAM chips on the CPU and viola, you have 16, 32, 512 megs of cache. or that DDR2 will be blown out of the water with the new standards. I like this kind of stuff.

 

[pm]

To summarize the leading nonvolatile contenders (others, feel free to quote this list and add to it , or correct it):
NRAM (Nano-ram) - http://en.wikipedia.org/wiki/NRAM
FRAM (FeRAM) - http://en.wikipedia.org/wiki/Ferroelectric_RAM
MRAM - http://en.wikipedia.org/wiki/Mram
PRAM - http://en.wikipedia.org/wiki/Phase-change_memory

Largest prototype built - that I could find (note: Mbit, not MByte):
NRAM: none yet
FRAM: 8Mb (Ramtron and TI)
MRAM: 4Mb (Freescale)
PRAM: 256Mb (Samsung), 128Mb (Intel), 128Mb (STMicroelectronics)

Looking at the prototypes, there is a clear winner - PRAM, AKA "phase-change RAM" or "Ovonic RAM". It may have the worst name of the bunch, but if I had to bet on any of them with my own money, for long-term commercial success, I'd choose PRAM hands-down.

They each have their pros and cons, but definitely PRAM is the farthest along in the development cycle. It has good density (particularly compared to NOR Flash), very impressive read and write speeds (compared to Flash), good long-term cycle reliability (~10^8 cycles), and very good long-term data storage integrity. In addition the ratio of an "on" resistance to an "off resistance" is very large on the Samsung prototype showing that it might be possible to create multi-level cells (like Intel's Strataflash RAM which holds 2 bits per flash cell) - perhaps even 3 or 4 bits per cell.

 

[RaynorWolfcastle]

Not totally related to the subject since it's volatile memory, but have you guys read the article in this month's Spectrum about Z-RAM? The technology seems promising, especially considering the amount of space taken up by cache in a modern microprocessor. I think I had read that Intel had also proposed some floating-body memory that doesn't require SOI at IEDM but the proceedings of the conference haven't been published yet.
Link

 

[pm]

Yeah, Z-RAM looks very interesting. I just read the Spectrum article ("Master's of Memory"). It was a little light on details, and I disagreed with several of the statements in it, but it was interesting reading. I haven't seen any details of larger prototypes, but I'm sure that they are coming. The density should be impressive - we'll see what the rest of the spec's look like when they hit the peer-reviewed journals.

I found this article on the Innovative Silicon website: http://www.innovativesilicon.com/en/pdf/z-ram.pdf