Samsung Announces 512GB DDR5 Memory That Is Twice as Fast as DDR4(hothardware.com)
hothardware.com
Samsung Announces 512GB DDR5 Memory That Is Twice as Fast as DDR4
https://hothardware.com/news/samsung-512gb-ddr5-memory-2x-faster-ddr4
32 comments
> used as System RAM, just as slightly slower System RAM
Intel Optane DIMM and Intel Optane SSD. Although Micron is selling their "Optane" Fab and Intel has yet to announce if they intend to buy it.
>such links might include optical fiber
Intel has been working on this for many years, Silicon Photonics and the goal is to have Compute, Memory and Storage in different "box" or even "Racks".
>can be connected via high-speed serial links
IBM OpenCAPI and OMI. Which allows up to 5PB of memory ( No more Big Data crap ) , and if I remember correctly with additional 10ns latency.
Intel Optane DIMM and Intel Optane SSD. Although Micron is selling their "Optane" Fab and Intel has yet to announce if they intend to buy it.
>such links might include optical fiber
Intel has been working on this for many years, Silicon Photonics and the goal is to have Compute, Memory and Storage in different "box" or even "Racks".
>can be connected via high-speed serial links
IBM OpenCAPI and OMI. Which allows up to 5PB of memory ( No more Big Data crap ) , and if I remember correctly with additional 10ns latency.
> Although Micron is selling their "Optane" Fab and Intel has yet to announce if they intend to buy it.
I have several close friends working at that fab and I am astounded that Micron is both still in business and hasn't caused a chemical disaster in Lehi yet. It's a fantastically mismanaged and unsafe workplace.
I have several close friends working at that fab and I am astounded that Micron is both still in business and hasn't caused a chemical disaster in Lehi yet. It's a fantastically mismanaged and unsafe workplace.
It's been tried but never achieved any significant commercial success.
https://en.wikipedia.org/wiki/Texas_Memory_Systems
https://en.wikipedia.org/wiki/I-RAM
https://en.wikipedia.org/wiki/HyperOs_HyperDrive
https://en.wikipedia.org/wiki/Texas_Memory_Systems
https://en.wikipedia.org/wiki/I-RAM
https://en.wikipedia.org/wiki/HyperOs_HyperDrive
It's not precisely what you're talking about, but you might be interested in Remote DMA:
https://en.m.wikipedia.org/wiki/Remote_direct_memory_access
https://en.m.wikipedia.org/wiki/Remote_direct_memory_access
> Look into the various ways that RAM can be connected via high-speed serial links
https://www.devever.net/~hl/omi
https://www.devever.net/~hl/omi
The problem with putting RAM at the end of a cable is that RAM latency is highly dependent on distance from the CPU.
Assuming RAM is 2 inches away from the cpu, and assuming the CPU is operating at 3 ghz, you are looking at 3 billion round trips per second over the distance of 2 inches, or a grand total of 12 billion inches of wire being crossed per second.
Electric signals are limited by the speed of light, though. In a vacuum, light travels at 299,792,458 meters per second, or 11,802,852,677 (11 billion) inches per second.
Do you see the bottleneck?
Assuming RAM is 2 inches away from the cpu, and assuming the CPU is operating at 3 ghz, you are looking at 3 billion round trips per second over the distance of 2 inches, or a grand total of 12 billion inches of wire being crossed per second.
Electric signals are limited by the speed of light, though. In a vacuum, light travels at 299,792,458 meters per second, or 11,802,852,677 (11 billion) inches per second.
Do you see the bottleneck?
That's not really how CPUs / RAM have worked since the 1980s. The CPU doesn't operate synchronously out of RAM, fetching data on each clock cycle. It operates from a hierarchical series of on-die caches, with only the L1 cache (typically a few 10s of kilobytes at most) operating close to how you describe. Logic on the CPU will send a series of commands to the RAM (along with data if it's a write), and there will be many commands 'in-flight' around the system at any given time, to hide the relatively high latencies involved (many 10s of nanoseconds). The actual propagation delay (around ~1 nanosecond/foot for cables) barely figures into it. Even the cables can have many 'bits' in flight at a time on them, and typically each 'direction' of the link forwards a clock along with the data (or it's embedded in the data stream) to avoid messy synchronization issues.
honest question: what about throughput?
I see the issue on latency, but suppose this system is being consumed by a large GPU or a traditional out of order CPU or DMA mechanism. If you can start reads and writes over a high throughput pipe on many chips, can't you also get higher throughput to keep multiple parallel operations busy while requests are in flight?
I see the issue on latency, but suppose this system is being consumed by a large GPU or a traditional out of order CPU or DMA mechanism. If you can start reads and writes over a high throughput pipe on many chips, can't you also get higher throughput to keep multiple parallel operations busy while requests are in flight?
No, I dont. Its ~30cm/ns, Fastest RAM available _ever_ never went below 7ns.
I do see the bottleneck!
But, short of having a "how to subvert the speed of light" discussion, which would be exceedingly long (and probably unproductive!) -- you've given me an idea!
Yes, you are correct that the speed of electrical propagation is limited, and does limit things!
We're completely agreed there!
OK, so here's my idea!
F--- the electrical cable entirely!
So, we have Quantum computers, Quantum bits, and all sorts of research on how to compute things with them, all kinds of professors and papers and companies and venture capital all researching how to do Quantum Computation...
Well, I say F--- all of that! (In a polite, friendly, "yes your work is really genius and I acknowledge all of your brilliant contributions kind of way!").
Here's the grail!
The grail of Quantum is NOT Quantum Computation -- but rather Quantum Communication!
In other words, get rid of the damn electrical cable, and
figure out a way to do that communication with a pair of connected-at-a-distance Quantum bits; that is -- Quantum Communication!
In other words,
Quantum Communication -- should replace wires and busses of all sorts, serial, parallel, electrical, light, what-have-you.
That's the damn grail!... (pardon my language!)
Not Quantum Computing!!! (brilliant though it is, I am not trying to knock it in any way, far from, quite the opposite!)
Quantum Communication -- replacing wires and busses of all sorts, serial, parallel, electrical, light -- would be the Holy Grail -- of being able to build bigger computers (like imagine close-to-infinite RAM -- on one motherboard! Close-to-infinite RAM! Well, it would be off that motherboard... but Quantum Communication, if it were available, would, for all intensive purposes, make that RAM so connected, would have the net effect -- of physically existing on the motherboard, even though in actuality it would not be so!)
So, to answer your question...
YES, I DO SEE THE BOTTLENECK!
But... equal-and-oppositely...
Do you see my point?
But, short of having a "how to subvert the speed of light" discussion, which would be exceedingly long (and probably unproductive!) -- you've given me an idea!
Yes, you are correct that the speed of electrical propagation is limited, and does limit things!
We're completely agreed there!
OK, so here's my idea!
F--- the electrical cable entirely!
So, we have Quantum computers, Quantum bits, and all sorts of research on how to compute things with them, all kinds of professors and papers and companies and venture capital all researching how to do Quantum Computation...
Well, I say F--- all of that! (In a polite, friendly, "yes your work is really genius and I acknowledge all of your brilliant contributions kind of way!").
Here's the grail!
The grail of Quantum is NOT Quantum Computation -- but rather Quantum Communication!
In other words, get rid of the damn electrical cable, and
figure out a way to do that communication with a pair of connected-at-a-distance Quantum bits; that is -- Quantum Communication!
In other words,
Quantum Communication -- should replace wires and busses of all sorts, serial, parallel, electrical, light, what-have-you.
That's the damn grail!... (pardon my language!)
Not Quantum Computing!!! (brilliant though it is, I am not trying to knock it in any way, far from, quite the opposite!)
Quantum Communication -- replacing wires and busses of all sorts, serial, parallel, electrical, light -- would be the Holy Grail -- of being able to build bigger computers (like imagine close-to-infinite RAM -- on one motherboard! Close-to-infinite RAM! Well, it would be off that motherboard... but Quantum Communication, if it were available, would, for all intensive purposes, make that RAM so connected, would have the net effect -- of physically existing on the motherboard, even though in actuality it would not be so!)
So, to answer your question...
YES, I DO SEE THE BOTTLENECK!
But... equal-and-oppositely...
Do you see my point?
You cannot communicate over a distance faster than the speed of light even using quantum phenomenon.
About 120+ years ago or so, if you would have said to the common man that it was possible for a heavier-than-air aircraft to fly, they would have said that that feat of engineering was physically impossible...
https://en.wikipedia.org/wiki/Wright_brothers
Today, after 120 years or so (roughly) of heavier-than-air flight, if you were to say that heavier-than-air aircraft flight was possible, no one would even do so much as "bat an eye" at that statement...
I had an old Physics Teacher who once (very wisely!) said:
"Given time, the impossible becomes possible, the possible becomes probable, and the probable becomes damn-near-likely to occur!"
It was like that for heavier-than-air flight.
I think that future history will show your statement to be incorrect at some point -- even though, in fairness to you, your statement might very well be true today, tomorrow, and in the immediate, near-term future...
"Given time, the impossible becomes possible, the possible becomes probable, and the probable becomes damn-near-likely to occur..."
Also, as a general rule, if something is apparently "not possible" (which yours truly highly doubts) -- then anyone who's worth their salt as a scientist needs to ask WHY multiple times -- and to keep "tunneling downward" across multiple levels, multiple substrata of WHY...
See, reach a certain level of WHY (which is really a cause, which sets of the whole cause-effect-cause-effect-etc. chain), understand it -- and you can control all of the effects which proceed out of that initial cause...
If we consider waves, for example, those which could occur in a rope or steel cable tied between two posts (compare to radio transmitter and receiver, even though there is no physical medium between them), but if we consider a rope or steel cable, and the waves which can travel along that medium -- they will travel at a certain speed, relative to wavelength (incidentally, all of the "can't go faster than light speed" stuff -- is tied to wavelength, and wavelength equations of hertzian waves -- that's the WHY).
But, there's something else going on in that rope or steel cable.
And that is, the instantaneous tension of a part of the rope or steel cable -- when a certain waveform is applied, for example, when someone starts vibrating or oscillating that rope or steel cable...
See, the waveform propagates at one speed relative to the rate of oscillation.
That is one form of propagation.
Waves of that nature -- will have a certain speed relative to their wavelength (size).
But if the rope or steel cable is in tension between two points, two poles or what have you -- it will propagate changes in that tension near instantly -- much faster than the waveform formed by the aforementioned oscillation or vibration!
The same principle is at play with railroad tracks.
That is, a train moves at one speed, one velocity, but if you're far ahead of the train, if you put your ear to the train tracks (and I highly highly recommend that no one do this -- this is said for explanatory purposes only!), but if someone were to put their ear to the track of a train which was some distance away -- they would hear the vibrations propagated in the train track at a much higher speed, a much higher velocity, than the speed of the train!
Well, same thing with light speed in this case.
Light is the train, the medium in which light travels through is the train track.
The train track is in tension, and by increasing vibrations as the train gets closer, it "knows" that a train is approaching!
The vibrations in the train tracks (train tracks have extremely high tension!) -- move at a faster rate of speed than the oncoming train!
So, while you might be right in your assessment in the short term, that Quantum Communication is impossible, I respectfully disagree as to what the long-term prospects and possibilities in this area are...
You might be right today... but for how much longer will that truth hold?
https://en.wikipedia.org/wiki/Wright_brothers
Today, after 120 years or so (roughly) of heavier-than-air flight, if you were to say that heavier-than-air aircraft flight was possible, no one would even do so much as "bat an eye" at that statement...
I had an old Physics Teacher who once (very wisely!) said:
"Given time, the impossible becomes possible, the possible becomes probable, and the probable becomes damn-near-likely to occur!"
It was like that for heavier-than-air flight.
I think that future history will show your statement to be incorrect at some point -- even though, in fairness to you, your statement might very well be true today, tomorrow, and in the immediate, near-term future...
"Given time, the impossible becomes possible, the possible becomes probable, and the probable becomes damn-near-likely to occur..."
Also, as a general rule, if something is apparently "not possible" (which yours truly highly doubts) -- then anyone who's worth their salt as a scientist needs to ask WHY multiple times -- and to keep "tunneling downward" across multiple levels, multiple substrata of WHY...
See, reach a certain level of WHY (which is really a cause, which sets of the whole cause-effect-cause-effect-etc. chain), understand it -- and you can control all of the effects which proceed out of that initial cause...
If we consider waves, for example, those which could occur in a rope or steel cable tied between two posts (compare to radio transmitter and receiver, even though there is no physical medium between them), but if we consider a rope or steel cable, and the waves which can travel along that medium -- they will travel at a certain speed, relative to wavelength (incidentally, all of the "can't go faster than light speed" stuff -- is tied to wavelength, and wavelength equations of hertzian waves -- that's the WHY).
But, there's something else going on in that rope or steel cable.
And that is, the instantaneous tension of a part of the rope or steel cable -- when a certain waveform is applied, for example, when someone starts vibrating or oscillating that rope or steel cable...
See, the waveform propagates at one speed relative to the rate of oscillation.
That is one form of propagation.
Waves of that nature -- will have a certain speed relative to their wavelength (size).
But if the rope or steel cable is in tension between two points, two poles or what have you -- it will propagate changes in that tension near instantly -- much faster than the waveform formed by the aforementioned oscillation or vibration!
The same principle is at play with railroad tracks.
That is, a train moves at one speed, one velocity, but if you're far ahead of the train, if you put your ear to the train tracks (and I highly highly recommend that no one do this -- this is said for explanatory purposes only!), but if someone were to put their ear to the track of a train which was some distance away -- they would hear the vibrations propagated in the train track at a much higher speed, a much higher velocity, than the speed of the train!
Well, same thing with light speed in this case.
Light is the train, the medium in which light travels through is the train track.
The train track is in tension, and by increasing vibrations as the train gets closer, it "knows" that a train is approaching!
The vibrations in the train tracks (train tracks have extremely high tension!) -- move at a faster rate of speed than the oncoming train!
So, while you might be right in your assessment in the short term, that Quantum Communication is impossible, I respectfully disagree as to what the long-term prospects and possibilities in this area are...
You might be right today... but for how much longer will that truth hold?
Thanks for the elaborate answer... "When you can explain a complex topic in a way that even a child can understand it, it means that you are truly an expert."
Ah, but, I don't write "to be an expert"... <g>
I write to:
clarify the way I think
!
So, what's the difference?
?
Well you see, if:
a) Someone writes something
and:
b) They are basically honest, at least with respect to themself, their own thoughts, in their own writings;
and
c) They are given a chance to review and edit and correct their own writings (in Law, we call this "Amending" something) after having written them;
Then, typically, as a result of these conditions:
d) They discover, and can subsequently think about, ("examine")
their own self-contradictions
...which if they are subsequently thought about, and subsequently resolved (again, in thought) -- will invariably lead to
better and clearer thinking...
We might call this the process of "self-examination" -- through writing...
I believe Socrates said something to the effect of "The unexamined life -- is not worth living".
Now, I don't know if that's true or not...
What I do know, is that I write to:
clarify the way I think
(And of course there are other reasons too, like communication, human communication... but it's not "to be an expert"... (What would I possibly gain from being "an expert", other than a title, a higher pay grade, and possibly more incompetency than the guy who's at the next pay grade higher than me? <g>))
(Oh, and sometimes I get good jokes, good humor, good comedy ideas -- from writing... but these are slag by-products of the writing process -- and not the norm...)
Anyway, that's why I do it...
Not "to be an expert"...
"The true knowledge -- consists in knowing that one knows nothing..."
-Socrates
I write to:
clarify the way I think
!
So, what's the difference?
?
Well you see, if:
a) Someone writes something
and:
b) They are basically honest, at least with respect to themself, their own thoughts, in their own writings;
and
c) They are given a chance to review and edit and correct their own writings (in Law, we call this "Amending" something) after having written them;
Then, typically, as a result of these conditions:
d) They discover, and can subsequently think about, ("examine")
their own self-contradictions
...which if they are subsequently thought about, and subsequently resolved (again, in thought) -- will invariably lead to
better and clearer thinking...
We might call this the process of "self-examination" -- through writing...
I believe Socrates said something to the effect of "The unexamined life -- is not worth living".
Now, I don't know if that's true or not...
What I do know, is that I write to:
clarify the way I think
(And of course there are other reasons too, like communication, human communication... but it's not "to be an expert"... (What would I possibly gain from being "an expert", other than a title, a higher pay grade, and possibly more incompetency than the guy who's at the next pay grade higher than me? <g>))
(Oh, and sometimes I get good jokes, good humor, good comedy ideas -- from writing... but these are slag by-products of the writing process -- and not the norm...)
Anyway, that's why I do it...
Not "to be an expert"...
"The true knowledge -- consists in knowing that one knows nothing..."
-Socrates
This is where Optane comes in. Faster than SSD, but larger than RAM:
https://www.youtube.com/watch?v=cwy4ujt0qHM
https://youtu.be/uHAfTty9UWY?t=263
https://www.youtube.com/watch?v=cwy4ujt0qHM
https://youtu.be/uHAfTty9UWY?t=263
No mention of latency. Presumably that means this will be higher latency than DDR4 (following recent trends to simultaneously increase DRAM bandwidth and latency).
Bw/latency comparison
https://www.anandtech.com/show/16143/insights-into-ddr5-subt...
https://www.anandtech.com/show/16143/insights-into-ddr5-subt...
It's worth noting there's a disconnect between the JEDEC standard latencies and what's actually available. It lists the DDR4 latencies at around 13-14ns but 10ns latency kits can be bought without paying a significant premium[1].
[1] https://pcpartpicker.com/products/memory/#Z=32768002&sort=pr...
[1] https://pcpartpicker.com/products/memory/#Z=32768002&sort=pr...
[deleted]
Latency often does increase with new generations of RAM.
But remember to compensate latency cycle counts with the faster cycles of higher speed RAM. Often the absolute time in nanoseconds hasn't changed as much as the cycle count numbers make it seem.
But remember to compensate latency cycle counts with the faster cycles of higher speed RAM. Often the absolute time in nanoseconds hasn't changed as much as the cycle count numbers make it seem.
It is a bit of a trade-off. For desktops and other personal devices you usually want lower latency. For servers and HPC you often want higher bandwidth.
Isn't the biggest problem with SSD latency generally that paralell reading / writing is not used within software that was optimized for hard disk?
> Twice as Fast
twice the transfer speed, same latency (if we are lucky). For reference
https://en.wikipedia.org/wiki/CAS_latency
https://www.crucial.com/articles/about-memory/difference-bet...
twice the transfer speed, same latency (if we are lucky). For reference
https://en.wikipedia.org/wiki/CAS_latency
https://www.crucial.com/articles/about-memory/difference-bet...
I didn't look too deeply into DDR5 but I am going to guess 512GB per DIMM will be using half channel per group of DRAM Rank.
Which I assume will only allow 8 DIMM per socket on a 16 Memory Channel CPU at a maximum of 4TB Memory per Socket.
Which I assume will only allow 8 DIMM per socket on a 16 Memory Channel CPU at a maximum of 4TB Memory per Socket.
Am I missing something here?
- The speed of this is 7,200 Mbps (lowercase "b").
- The speed of a fast SSD is 7,000 MBps (uppercase "B").
Why am I paying for tons of ram to cache anymore? (I'm ignoring wear & tear for this question.)
Referenced SSD speed source from here: https://www.gamingpcbuilder.com/best-m-2-nvme-ssd/
--------
EDIT: found the answer here: "Samsung's latest module would deliver around 57.6 GB/s transfer speeds on a single channel"
https://www.engadget.com/samsung-unveils-a-512-gb-ddr-5-ram-...
- The speed of this is 7,200 Mbps (lowercase "b").
- The speed of a fast SSD is 7,000 MBps (uppercase "B").
Why am I paying for tons of ram to cache anymore? (I'm ignoring wear & tear for this question.)
Referenced SSD speed source from here: https://www.gamingpcbuilder.com/best-m-2-nvme-ssd/
--------
EDIT: found the answer here: "Samsung's latest module would deliver around 57.6 GB/s transfer speeds on a single channel"
https://www.engadget.com/samsung-unveils-a-512-gb-ddr-5-ram-...
On SSD latency on write is much longer and it is block (512B to 1K) read/write only.
DDR is random per byte/word.
DDR is random per byte/word.
With such memory capacity it seems we now can store entire operating system in ram. While we at it we can get rid of a file system since everything is in ram anyways
So, I'm wondering (and maybe something like this already exists) what if RAM could be placed at the end of a high-speed serial cable of some sort. Like Firewire, Ethernet, Fast USB, or some kind of LVDS high-speed data serial cable...
Now, this RAM (because it would allow for long cable sizes, because we'd like to connect more of it to a PC, and thus the serial cable speed would be a bit reduced due to length) would not be intended as System RAM -- but more like a faster-than-SSD hard drive -- although perhaps it could be used as System RAM, just as slightly slower System RAM...
Note To Future Self: Look into the various ways that RAM can be connected via high-speed serial links (also, in the future, such links might include optical fiber...). So, high speed serial links AND optical fiber...