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How DRAM changed the world

micron.com

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Re: How DRAM changed the world

#71

Post by specialist »

rob74 wrote: post #46
emptiestplace wrote: post #22

Earlier quoted context omitted.

> Going from 8MB to 32MB in the 90s is still comparable to going from 8GB to 32GB today. This statement makes it difficult to believe you were there.

Of course, the really significant step back then was being able to go from 640 kB (+/-) to more than 1 MB ( https://en.wikipedia.org/wiki/Conventional_memory ).

Yup.

We maxed our Tandy (Radio Shack) 286 boxen, juiced to a blistering 8mhz, with 2.5mb RAM. I got blisters from stuffing RAM into daughter boards.

https://en.wikipedia.org/wiki/Expanded_memory#Expansion_boar...

Twas early years of PC-based image scanning and processing. We only had 1 image capture board. The boot's POST duration for 2.5mb was ridiculous. So after a cpature, my coworker (hi Tim Hall!) would ever so quickly yank the board out of a running box (now doing image processing) to be used in another box.

Multitasking!

As I remember it, the jump to 386 (much delayed by Micron's protectionist racket) was the next biggest step up.

Re: How DRAM changed the world

#72

Post by [deleted] »

neom wrote: post #3

I miss RAM. I feel like if you lived through that 90s RAM frenzy, you probably miss RAM too. It was crazy how quickly we move through SDRAM/DDR, prices dropped and you could make real increases in performance year over year for not much money. I'm sure some of it was the software being able to capture the hw improvements, but that certainly was my fav period in tech so far.

[deleted]

Re: How DRAM changed the world

#73

Post by [deleted] »

neom wrote: post #3

I miss RAM. I feel like if you lived through that 90s RAM frenzy, you probably miss RAM too. It was crazy how quickly we move through SDRAM/DDR, prices dropped and you could make real increases in performance year over year for not much money. I'm sure some of it was the software being able to capture the hw improvements, but that certainly was my fav period in tech so far.

[deleted]

Re: How DRAM changed the world

#75

Post by crest »

guerrilla wrote: post #44
RF_Savage wrote: post #29

Earlier quoted context omitted.

That 4x the price does also explain why it has not happened.

Yeah but why don't we have like 500MB of SRAM per 8GB of RAM. Certain addresses could be faster, in the same way /dev/shm/ is faster.

AMD offers CPUs with over 768MiB of cache if you're willing and able to afford them.

Re: How DRAM changed the world

#76

Post by crest »

Salgat wrote: post #18
MichaelZuo wrote: post #2

Dennard scaling for SRAM has certainly halted, as demonstrated by TSMC’s 3nm process vs 5 nm. What’s the likely ETA for DRAM?

5nm can hold roughly a gigabyte of SRAM on a cpu-sized die, that's around $130/GB I believe. At some point 5nm will be cheap enough that we can start considering replacing DRAM with SRAM directly on the chip (aka L4 cache). I wonder how big of a latency and bandwidth bonus that'd be. You could even go for a larger node size without losing much capacity for half the price.

SRAM also requires more power than DRAM and the simple regular structure of SRAM arrays compared to (other) logic makes it possible to get good yield rates through redundancy and error correction codes so you could have giant monolithic dies, but information can't exceed the speed of light in a medium. There just isn't enough time for the signals to propagate to get the latency you expect of a L3 cache out of gigabytes (in relative terms) far away big dies containing gigabytes of SRAM. Also moving that the data would to perform computations without caching would be terrible wasteful given how much energy is needed just to move the data. Instead you would probably end up with something closer to the computing memory concept to map computation to ALUs close to the data with an at least two tier network (on-die, inter-die) to support reductions.

Re: How DRAM changed the world

#77

Post by OptionOfT »

bloedsinnig wrote: post #55
aidenn0 wrote: post #28

Earlier quoted context omitted.

It's insufficient for large theaters and barely sufficient for medium theaters. 1080p is plenty for most home theaters (though with the so-so quality of streaming, I wonder to what degree macroblocks are the new pixels)

1080p looks different to 4k. Just because its 'plenty' doesn't mean 4k doesn't matter. And we are at 2024, i own a 4k lg oled display now for years. Why not leverage it? Just because 1080p is 'plenty'?

The problem with 4k, which 99% of people only experience as a stream, is that it's over-compressed. A 1080p BluRay is 36 Mbit.

Netflix 4k is 15 Mbit.

So unless I see people mentioning the media, I am always weary of the comparison.

Re: How DRAM changed the world

#79

Post by kstrauser »

seunosewa wrote: post #10

The article doesn't properly explain how DRAM is different from SRAM. DRAM has to constantly refresh itself in order not to 'forget' its contents.

Why would we use DRAM, then? It seems better not to have to refresh it all the time.

(I think I more or less know, but I’d rather talk about it than look it up this morning.)

Re: How DRAM changed the world

#80

Post by kstrauser »

hajile wrote: post #20
MichaelZuo wrote: post #2

Dennard scaling for SRAM has certainly halted, as demonstrated by TSMC’s 3nm process vs 5 nm. What’s the likely ETA for DRAM?

Years ago. DRAM uses a capacitor. Those capacitors essentially hit a hard limit at around 400MHz for our traditional materials a very long time ago. This means that if you need to sequentially read random locations from RAM, you can't do it faster than 400MHz. Our only answer here is better AI prefetchers and less-random memory patterns in our software (the penalty for not prefetching is so great that theoretically l…

What does “faster than 400MHz” mean in this context? Does that mean you can’t ask for a unit of memory from it more than 400M times a second? If so, what’s the basic unit there, a bit? A word?

I built a little CPU in undergrad but never got around to building RAM and admit it’s still kind of a black box to me.

Bonus question: When I had an Amiga, we’d buy 50 or 60ns RAM. Any idea what that number meant, or what today’s equivalent would be?

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