• abhibeckert@lemmy.world
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    8 months ago

    It runs at 120 GB/s…

    As a Mac user that sounds pretty shit. RAM in a MacBook Pro runs at 400GB/s and that’s a CPU which will be obsolete in the next few months, with a new one coming that’s expected to be more like 500GB/s.

    Sure, modular memory is great. But not if it comes with a performance penalty like that.

    • falkerie71@sh.itjust.works
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      8 months ago

      Apple M3 uses LPDDR5 and have transfer speeds of up to 6400 MT/s while LPDDR5X will have 8533 MT/s. LPCAMM2 is the connector type to replace SO-DIMM slots, it still uses LPDDR chips. According to this article, it would support speeds of up to 9600 MT/s. So unless I’m missing something, shouldn’t speed not be much of a concern? I’m open to corrections.

      • Victor@lemmy.world
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        8 months ago

        Megatransfers? Or what does the T stand for? And how does a “transfer” (if so) translate to bytes?

        • bonus_crab@lemmy.world
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          8 months ago

          Yeah mega transfers. 1 transfer is 8 bytes. the DD in DDRX is double data so it can send 2 transfers per channel per clock. CPUs pretty much always use 2 channels, so the formula is just GBps = 32 * MT/s. My PC has 6000MT/s DDR5 in a dual channel config so thatd be 192GBps.

          Idk how apple is getting above 300GBps, maybe theyre counting the integrated GPU as part of the total. GPUs often have 4 or 6 or 8 channels so thatd make sense…

          • Victor@lemmy.world
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            8 months ago

            Thank you for going into detail.

            Okay so, 1 T = 8 B. DD => 2 T/channel. And with 2 channels we get 4 T, so 4 × 8 = 32. Okay I get you. Thanks so much. 🙂

            Yeah that’s a crazy number with 300-500 GBps if DDR5 is doing around 200… Absolutely insane actually. But yeah, good theory about the GPU. Those bastards, padding the numbers.