Totaly misunderstanding of DDR SDRAM memory interfaces and DRAM

By: Heikki Kultala (heikki.ku.ltala.delete@this.gmail.com), April 7, 2021 12:36 pm
Room: Moderated Discussions
Brett (ggtgp.delete@this.yahoo.com) on March 25, 2021 5:17 pm wrote:
> Jon Masters (jcm.delete@this.jonmasters.org) on March 23, 2021 3:31 pm wrote:
> > The "Intel Unleashed" event this afternoon featured the announcement of
> > a new "IDM 2.0" model including a second attempt at doing a foundry:
> >
> > https://www.anandtech.com/show/16573/intels-new-strategy-20b-for-two-fabs-meteor-lake-7nm-tiles-new-foundry-services-ibm-collaboration-return-of-idf
>
> Intel’s unit growth is weak and each shrink is reducing die size by perhaps a third.
> So where does Intel possibly need 20 billion in new fabs when a shrink should close fabs?
>
> At 5nm you can put 256 cores on a chip but DDR cannot possibly feed these chips.
> I am predicting RAM goes on chip perhaps being called L4, and DRAM if included is used much
> like SSD’s for paging. Going from server chiplets to reticle limited dies with the bulk
> of the area RAM of some type and CPU’s along two edges with a slight gap in the middle
> so dies can be split in half for gamer chips. This would use 20 billion in fab space.

This post is clueless in some many different ways.

You are totally confusing DDR SDRAM memory interface and DRAM.

There are already chips that have 6144-bit bus to DRAM memory. This gives HUGE bandwidth.

There are also already DRAM memories that have 21 Gbps transfer rate per pin. These memories also have HUGE bandwidth.

And, CPU workloads are not very bandwidth limited, they ​are more latency limited.

And paging to DRAM to makes absolutely no sense at all. Paging has to be done for hard disks and NAND-flash-based SSDs because those are not byte-addressable. DRAM is. Paging just has terrible OS overhead.

"RAM of some type". There is no other RAM type than SRAM that can be manufactured with modern logic CMOS processes, and SRAM is way too sparse/expensive. In order to have gigabytes of fast memory, there is no other sensible option than DRAM. (though, a new layer of slower, cheaper memory may/will appear between the DRAM and the NAND flash)


What will happen (and has already partially happened) is that DRAM will just move from DIMMs on the motherboard into the same package where the processor is.


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TopicPosted ByDate
Intel's IDM 2.0 announcementJon Masters2021/03/23 03:31 PM
  Intel's IDM 2.0 announcementRayla2021/03/23 03:45 PM
    Intel's IDM 2.0 announcementdmcq2021/03/23 04:30 PM
    commitment to foundry, shutting down fabless talkDaniel B2021/03/23 04:46 PM
      commitment to foundry, shutting down fabless talkKester L2021/03/23 04:56 PM
        commitment to foundry, shutting down fabless talkanonymou52021/03/24 12:57 AM
          commitment to foundry, shutting down fabless talkme2021/03/24 03:25 AM
            commitment to foundry, shutting down fabless talkJoe2021/03/24 05:56 AM
              commitment to foundry, shutting down fabless talkMichael S2021/03/24 06:47 AM
                commitment to foundry, shutting down fabless talkme2021/03/24 07:04 AM
      commitment to foundry, shutting down fabless talkJames2021/03/24 03:39 AM
        Intel gutted 7 nmme2021/03/24 03:48 AM
          Intel gutted 7 nmDoug S2021/03/24 08:20 AM
            Intel gutted 7 nmanon2021/03/25 12:43 PM
              Intel gutted 7 nmeh2021/03/26 02:36 AM
                Intel gutted 7 nmAdrian2021/03/26 08:58 AM
                  Intel gutted 7 nmwumpus2021/03/26 09:53 AM
                  Intel gutted 7 nmme2021/03/26 10:11 AM
                  Intel gutted 7 nmMaxwell2021/03/26 02:21 PM
                    Intel gutted 7 nmYoav2021/03/29 01:06 AM
              Intel gutted 7 nmDoug S2021/03/26 09:43 AM
                Intel gutted 7 nmanon2021/03/26 03:39 PM
                  Intel gutted 7 nmNoSpammer2021/03/26 08:46 PM
                    Intel gutted 7 nmAdrian2021/03/26 11:57 PM
                      Intel gutted 7 nmAndrey2021/03/28 06:18 PM
                    Intel gutted 7 nmanon2021/03/27 05:52 AM
                    Intel gutted 7 nmwumpus2021/03/27 12:16 PM
                  Intel gutted 7 nmDoug S2021/03/27 05:08 PM
                    Intel gutted 7 nmanon2021/12/13 03:05 PM
                      Intel gutted 7 nm---2021/12/13 04:31 PM
                      Intel gutted 7 nmDoug S2021/12/13 09:34 PM
                        Intel gutted 7 nmanon2021/12/13 10:41 PM
                          Intel gutted 7 nmDoug S2021/12/14 11:38 AM
                            Intel gutted 7 nmanon2021/12/14 11:58 AM
                            Feed the Troll less (unless you are enjoying it!)Mark Roulo2021/12/14 01:52 PM
                Intel gutted 7 nmblue2021/03/27 10:16 AM
                  Intel gutted 7 nmme2021/03/27 12:22 PM
                  Intel gutted 7 nmDoug S2021/03/27 05:14 PM
                    Intel gutted 7 nmDavid Kanter2021/04/07 09:06 PM
                      Intel gutted 7 nmDoug S2021/04/08 12:38 PM
        commitment to foundry, shutting down fabless talkDaniel B2021/03/24 08:08 AM
      commitment to foundry, shutting down fabless talkDoug S2021/03/24 08:12 AM
      commitment to foundry, shutting down fabless talkMaxwell2021/03/25 11:16 AM
        commitment to foundry, shutting down fabless talkme2021/03/25 11:38 AM
          commitment to foundry, shutting down fabless talkAdrian2021/03/25 01:01 PM
            commitment to foundry, shutting down fabless talkme2021/03/27 12:57 PM
    A lot has changed since thenDoug S2021/03/24 08:01 AM
    Intel's IDM 2.0 announcementGabriele Svelto2021/03/25 03:17 AM
  Intel's IDM 2.0 announcementBeastian2021/03/23 05:39 PM
    Intel's IDM 2.0 announcementJames2021/03/24 03:14 AM
      Intel's IDM 2.0 announcementme2021/03/24 03:37 AM
        Intel's IDM 2.0 announcementJames2021/03/24 03:53 AM
      Intel's IDM 2.0 announcementanonymou52021/03/24 08:39 AM
    Intel's IDM 2.0 announcementJukka Larja2021/03/24 06:05 AM
    Intel's IDM 2.0 announcement - Hyper-scalers as customersBjörn Ragnar Björnsson2021/03/24 06:19 PM
  5nm the end of DRAM?Brett2021/03/25 05:17 PM
    What is next after DDR5?Ganon2021/03/25 05:56 PM
      What is next after DDR5?wumpus2021/03/26 09:10 AM
        What is next after DDR5?Brett2021/03/26 04:39 PM
          What is next after DDR5?wumpus2021/03/28 10:44 AM
      What is next after DDR5?Brett2021/03/27 04:27 PM
        What is next after DDR5?Doug S2021/03/27 05:18 PM
      What is next after DDR5?Anononymous Coward2021/03/30 07:03 AM
        What is next after DDR5?Andrey2021/03/30 09:09 AM
          What is next after DDR5?David Hess2021/04/04 08:52 PM
      What is next after DDR5?David Hess2021/04/04 08:45 PM
        What is next after DDR5?Doug S2021/04/05 06:57 AM
          What is next after DDR5?David Hess2021/04/05 10:45 AM
          Same costAnon2021/04/05 11:31 AM
            Same costDavid Hess2021/04/05 08:26 PM
            Same costMaxwell2021/04/06 07:17 PM
              Same costDavid Hess2021/04/07 02:35 PM
          What is next after DDR5?wumpus2021/04/07 09:06 AM
      L4 is not a memory technologyHeikki Kultala2021/04/07 12:38 PM
        DRAM cachewumpus2021/04/08 08:24 AM
        Intel iGPU memory was eDRAM, not SRAMMark Roulo2021/04/08 11:31 AM
          I am not talking about the eDRAM. I am talking about the cache that is L3 for CPUHeikki Kultala2021/04/08 11:09 PM
            I am not talking about the eDRAM. I am talking about the cache that is L3 for CPURobert Williams2021/04/09 11:24 AM
              This STILL has NOTHING to do with the eDRAM. I am talking about the SRAM LLCHeikki Kultala2021/04/09 12:57 PM
                This STILL has NOTHING to do with the eDRAM. I am talking about the SRAM LLC---2021/04/09 01:40 PM
    5nm the end of DRAM?Rayla2021/03/26 09:28 AM
      5nm the end of DRAM?riy2021/04/08 06:26 AM
        5nm the end of DRAM?Michael S2021/04/08 11:51 AM
    5nm the end of DRAM?Doug S2021/03/26 09:52 AM
      5nm the end of DRAM?wumpus2021/04/07 09:10 AM
        5nm the end of DRAM?Robert Williams2021/04/07 11:05 AM
    Totaly misunderstanding of DDR SDRAM memory interfaces and DRAMHeikki Kultala2021/04/07 12:36 PM
      Totaly misunderstanding of DDR SDRAM memory interfaces and DRAManonymou52021/04/07 01:13 PM
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