[HN Gopher] JEDEC publishes GDDR7 graphics memory standard
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JEDEC publishes GDDR7 graphics memory standard
Author : ksec
Score : 74 points
Date : 2024-03-05 18:57 UTC (4 hours ago)
(HTM) web link (www.jedec.org)
(TXT) w3m dump (www.jedec.org)
| paddy_m wrote:
| How much relevance does JEDEC still have?
|
| I would think NVIDIA in particular and other chip
| makers/integrators like apple make up their own standards now. It
| also seems less relevant because memory is rarely interchangeable
| anymore
| sliken wrote:
| Do you have any evidence that Nvidia or Apple are using non-
| standard memory chips? Link? From what I can tell they are both
| using standard chips, but very wide memory interfaces. Apple's
| lowest end is 128 bit, but offer 256, 512, and 1024 bit wide
| memory interfaces for more bandwidth, which is mostly a benefit
| for the iGPU in all of Apple's m series CPUs. This is part of
| why Apple are pretty good at LLMs, especially those needing
| more ram than is in even the most expensive GPUs.
|
| Sad that the vast majority of x86-64 laptops and desktops have
| the same bus width of decades ago, while the core counts are
| ever increasing.
| jsheard wrote:
| Nvidia and Micron came up with GDDR6X, which isn't a JEDEC
| standard. JEDEC did standardize GDDR5X before that, but only
| Micron ever made it and only Nvidia ever used it AFAIK.
| zeusk wrote:
| JEDEC never "standardized" GDDR6x that Nvidia does use;
| Micron and Nvidia worked closely on both GDDR6x and GDDR5x
| hedgehog wrote:
| Apple and NVIDIA are both members of JEDEC...
| monocasa wrote:
| HBM is a JEDEC spec these days. Apple's on package memory is
| still LPDDR.
| ajross wrote:
| JEDEC isn't a memory technology monopoly or anything, they're
| just a standards organization. You have a situation where lots
| of companies need to make products that interoperate, but
| interoperation is complicated in electrical engineering. There
| are a *lot* of ways to get a memory interconnect wrong.
|
| So the solution is to pick (or create) a separate, notionally
| independent body staffed and supported by representatives of
| all the relevant stakeholders, and have them write "standards"
| that everyone agrees to adhere to. The body doesn't invent the
| technology, that happens at the individual chip companies. They
| then present their proposals to JEDEC[1] and everyone argues
| and agrees on what will go into GDDR19 or whatnot. And JEDEC
| then publishes the standards for all to see.
|
| [1] Or whoever, JEDEC does DRAM, but there's a USB Consortium,
| Bluetooth SIG, WiFi is under IEEE, etc...
| pillusmany wrote:
| Standardized memory chips allows economy of scale to work.
| Dalewyn wrote:
| >How much relevance does JEDEC still have?
|
| Ah, a FOSSy dev insistent that his bits are _gibi-_ and _mebi-_
| and _kibi-_ bytes.
| sliken wrote:
| Doubling the channels from GDDR6 sounds good, the speed of light
| isn't changing, so at least we can handle more parallelism with
| the same latency.
| oorza wrote:
| The ratio of light speed to the area of the universe is so
| stupidly small that I'm convinced our simulation is determining
| how low the speed of light can get before interstellar travel
| is outright impossible.
| adtac wrote:
| With sufficiently advanced technology, travelling between
| stars will be more of a transfer of your consciousness using
| interstellar WiFi (remember to set TCP_NODELAY!) rather than
| transporting slow and heavy atoms. You just get transferred
| from one biological substrate to another. None of the time
| dilation, all of the space exploration.
| Phelinofist wrote:
| But that would still be limited by the speed of light,
| right?
| adtac wrote:
| Of course, everything is. Doubling the speed of light
| means your network packets get there twice as fast, but
| accelerating matter to relativistic speeds, which too is
| limited by the speed of light, has less marginal utility
| from the doubling when it comes to energy needed for
| acceleration/deceleration and time dilation.
| stronglikedan wrote:
| Maybe quantum entanglement, where the original "portals"
| would be set up around the universe at the speed of
| light, but then data could henceforth be transferred
| between the portals at the speed of entanglement.
| omneity wrote:
| You're thinking of latency vs bandwidth/throughput. You
| might not improve on the latency part (speed of light),
| but you can increase the bandwidth (amount of data
| transferred per unit of time) just like a highway with
| more lanes can carry more people without increasing the
| individual speed of cars. You might even _decrease_ car
| speed and still get an improved throughput overall.
| parl_match wrote:
| Yeah, but you still need to get some bodies out there.
| WJW wrote:
| > all of the space exploration.
|
| How does the receiving technology get built? Surely at
| least someone will have to go there the first time, and
| they will have to take the long way. It will still be quite
| a problem to get to a system 10k light years away.
| kraquepype wrote:
| My inner sci-fi geek tells me that by this time, we
| discover faster than light travel, only it isn't
| compatible with life as we know it.
|
| So we ship off these receivers to circumvent that
| limitation. Instead of travelling ourselves, we can send
| off our consciousness to inhabit a human-life analog to
| explore.
|
| What that does to your psyche, and your body in limbo,
| are probably good material for a story, if it hasn't
| already been written.
| cyanydeez wrote:
| My inner geek tells me it's more likely humans will plug
| themselves into the matrix because it'll be far more
| receptive to technological advances than actual
| exploration.
|
| At best, you'll throw a bunch of nanoprobes everywhere to
| get new entropy into the system.
| cstrahan wrote:
| You just have to first hack (or maybe even just ask
| nicely) another suitable species (or their technological
| artifacts) wherever you want to go, and have them create
| the biological substrate and download/upload mechanism on
| their end. This limits travel to already inhabited
| corners of the universe, but that's better than nothing I
| suppose.
|
| The tricky thing is that hacking is usually an iterative
| process, and these iterations are going to be an extreme
| exercise in patience.
|
| Actually, another tricky thing: how do you know that the
| other end is actually cooperating? If the aliens are
| dicks they could give you the thumbs up while having zero
| intention to reconstitute your consciousness. If you
| wanted to round-trip some brave soul as a means of
| verifying everything works, they could just send one of
| their own minds back instead, just for the fun of
| wreaking havoc.
| riskable wrote:
| > The tricky thing is that hacking is usually an
| iterative process, and these iterations are going to be
| an extreme exercise in patience.
|
| No kidding! On the first try you accidentally end up
| causing a revolution because the targets/specimens ended
| up learning about the scientific method, gunpowder, and
| other dangerous things instead of just getting a proper
| advanced consciousness installed. So now all you can do
| is try to shape said species technological progress
| towards building the correct technology that you can
| hijack for your own purposes when ready.
|
| "Just be patient"
| adtac wrote:
| Is YC accepting applications for interstellar body rental
| stations like Hertz is for cars? I'd bootstrap it, but I
| think this requires venture scale funding.
| colejohnson66 wrote:
| Well, Hertz is selling off their whole Extraterrestrial
| Vehicle (EV) fleet, so it's probably not profitable
| enough for VCs.
| TaylorAlexander wrote:
| I'm of the view that you can possibly duplicate
| consciousness but you can never send "me". I'm stuck on the
| consciousness I've got. If you tried to upload my
| consciousness somewhere I'd still be sitting here like "hey
| look there's another one of me", but I'd not experience
| some shift in perspective myself.
| foobarian wrote:
| I find this a scary topic, like touching a hot stove. Try
| as hard as I can but I can't figure out (and overall
| nobody has so far) how the "self" experience works.
| adtac wrote:
| No, you _are_ your consciousness. The self exists only in
| the story the mind tells itself, so both versions would
| think they are the original you.
|
| Besides, the serialisation process is a form of quantum
| measurement. Depending on how coarse-grained it is, there
| might be no way to take a snapshot without modifying you
| (maybe the measurement process turns the original brain
| matter into soup).
| pricecomstock wrote:
| They would think they are the original you, but I think
| the GP was saying that the original perspective would
| continue on the original consciousness-
| continuity/body/hardware.
|
| Cloning a hard drive can produce the same data, but
| without any networking, there's no reason for the
| original machine to know anything from the perspective of
| the new one
| joshspankit wrote:
| Who says we're not doing that already and just calling it
| dreams?
| bitwize wrote:
| In elementary school I read a kids' novel, called _My Trip
| to Alpha I_ , that had precisely this as a McGuffin. The
| main character travels to visit his aunt and uncle by
| "Voya-Code", in which his consciousness is transmitted to
| an android body on the destination planet.
| drtgh wrote:
| >will be more of a transfer of your consciousness
|
| Sounds like a copy, not a transfer. If you didn't
| physically transport the atoms, the matter, you would end
| up with two duplicates living at different places and time,
| and with different ways of thinking after the copy, as the
| living experiences will diverge from that moment.
|
| This unless you exterminate the original with each copy.
| Also should be considered each copy may lose information,
| degrade (signal integrity through distance, number of
| travels, and so on).
| hnuser123456 wrote:
| Or is it the ratio of your lifespan to the age of the
| universe? The universe is only about 3x bigger
| instantaneously than it is when transversed at lightspeed.
| The ratio of the age of the universe to your expected
| lifespan is about 8 orders of magnitude.
| pillusmany wrote:
| Our solar system deployed a black domain for deterrence.
| ko27 wrote:
| "Ratio of light speed to the area of the universe" does not
| determine how far _you_ can travel in a set amount of time,
| because time dilation exists.
| znpy wrote:
| Just checking my intuition: could we still get a speedup via
| pipelined execution and branch prediction?
|
| From what i see reading https://en.wikipedia.org/wiki/Multi-
| channel_memory_architect... different channels could, in
| theory, be used "autonomously of each other".
| Lramseyer wrote:
| Controllers kind of do that. At the end of the day, it's what
| makes designing a memory controller so difficult (and I'm not
| even talking about the Phy, those things are straight up
| cursed!) We see these eye popping numbers for maximum
| potential bandwidths, but the reality is a bit more
| complicated. There's a lot that goes on behind the scenes
| with opening and closing memory banks, refreshes, and general
| read and write latencies. Unoptimized prediction algorithms
| (as they are programmable) can result in losing _half_ of
| your performance.
| colechristensen wrote:
| >the speed of light isn't changing
|
| Oh but the speed of the signal does depend quite a lot on the
| transmission medium. In Cat-6 signals travel 2/3 _c_. Can 't
| find a quick reference for on-die or motherboard kinds of
| interconnects. If you had optical interconnects traveling
| through vacuum in a silicon chip, that's a full 50% faster (as
| in lower travel time for one bit over a distance) than Most
| copper ethernet.
|
| https://en.wikipedia.org/wiki/Velocity_factor
| Scene_Cast2 wrote:
| One interesting thing to note is that all the high speed
| interconnect standards (GDDR, PCIE, USB, Ethernet) are moving (or
| have already moved) to RF-style non-binary communication (as
| opposed to bumping up clock speeds or increasing pin count). I
| wonder what the next steps will be for interconnects - full-blown
| baseband style transceivers with QAM perhaps?
| wmf wrote:
| Optical communication is using QAM so that's probably the next
| step.
| klysm wrote:
| Sharp signal edges are hard to get at higher frequencies - it
| seems quite natural
| SmellTheGlove wrote:
| This is probably a stupid question but I don't claim any
| knowledge here. Even though interconnect standards are moving
| to non-binary communication, doesn't the signal eventually need
| to be converted back to a bitstream at its destination? Does
| this just push the bottleneck around, or do I just not
| understand the problem being solved? It's almost certainly the
| latter and I'd love to understand more.
| kevvok wrote:
| You're right that the signals have to be converted back into
| bits at the destination. Basically, this solves the problem
| of pumping those bits at high speed across traces on a
| circuit board vs within a chip. The longer a signal has to
| go, the harder it is to maintain its integrity.
| wmf wrote:
| A serializer/deserializer (serdes) is used to convert between
| high-speed serial I/O outside the chip (e.g. 100 Gbps) and
| lower-clocked parallel signals inside the chip (e.g. 64 bits
| at 1.5 GHz). Using serial protocols reduces the cost and
| thickness of cables while parallel wires are cheaper inside
| the chip.
| ak217 wrote:
| Not a stupid question - you can think of the problem by
| analogy with RF engineering. You have very high performance
| digital logic and precise clocks on the chip that you can use
| to encode/decode (convolve/deconvolve) bits into waveform
| signals and time those signals before they leave the chip at
| minimal latency/power expense. Once the bits are off the
| chip, you have no such resource and are dealing with all
| kinds of impedance and noise issues, which is why there are
| separate circuits/logic dedicated to training and calibration
| of the encoding parameters of the signals sent over the wire
| in DRAM chips.
|
| This more complex encoding scheme is just the next level in
| that process, indeed moving it closer to techniques used in
| RF engineering.
| imtringued wrote:
| Unless Nvidia can somehow massively increase memory capacity, it
| is looking bleak for them in the consumer AI inference space.
| From the left Apple has a fully integrated SoC with insane memory
| bandwidth and capacity, from the right AMD is tackling the FLOPs
| advantage using their XDNA AI Engines that they got from their
| Xilinx acquisition and they are going to open source the compiler
| for their AI Engines. The only competitive advantage that NVidia
| has left is its high memory bandwidth, but even that is being
| threatened by Strix Point so they will need to adopt GDDR7 with
| 32 GB to 64GB VRAM fast or they will become irrelevant except for
| training. Oh and by the way AMD GPUs will stay completely
| irrelevant for AI so that explains why they didn't want to waste
| so much time on ROCm for consumer GPUs. Nobody is going to buy
| those for AI anymore by the end of the year.
| rubatuga wrote:
| AMD was the first to introduce consumer HBM cards.
| IshKebab wrote:
| I mean... CUDA. nVidia is fine.
| wmf wrote:
| It's not clear that the "consumer (local) AI inference space"
| is a real market. Ultimately Nvidia has access to all the same
| technologies as their competitors and better software so
| anything they can do Nvidia can do better... if they want to.
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