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Cake day: June 2nd, 2023

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  • You’ve made me uncertain if I’ve somehow never noticed this before, so I gave it a shot. I’ve been dd-ing /dev/random onto one of those drives for the last 20 minutes and the transfer rate has only dropped by about 4MB/s since I started, which is about the kind of slowdown I would expect as the drive head gets closer to the center of the platter.

    EDIT: I’ve now been doing 1.2GB/s onto an 8 drive RAID0 (8x 600GB 15k SAS Seagates) for over 10 minutes with no noticable slowdown. That comes out to 150MB/s per drive, and these drives are from 2014 or 2015. If you’re only getting 60MB/s on a modern non-SMR HDD, especially something as dense as an 18TB drive, you’ve either configured something wrong or your hardware is broken.


  • This is for very long sustained writes, like 40TiB at a time. I can’t say I’ve ever noticed any slowdown, but I’ll keep a closer eye on it next time I do another huge copy. I’ve also never seen any kind of noticeable slowdown on my 4 8TB SATA WD golds, although they only get to about 150MB/s each.

    EDIT: The effect would be obvious pretty fast at even moderate write speeds, I’ve never seen a drive with more than a GB of cache. My 16TB drives have 256MB, and the 8TB drives only 64MB of cache.










  • Aside from letting you cram more circuitry onto the same size chip, smaller transistors means you can get better power efficiency and reduce heat output.

    Basically, even if you just take an existing design and use it to make chips at a smaller node size, you get chips which run cooler and with less power. Those chips can then get you the same performance with better efficiency (e.g. same speed but better battery life), or you can crank up the speed so that you get more speed for the same amount of power as the original.

    And as mentioned above, because the transistors are smaller, you can fit more stuff onto the chip. So you can make even more complex chips which also still run more efficiently than their predecessors (both because of the direct power savings from using smaller transistors, and because designs become more efficient).



  • Yeah, I know it can be mismatched sizes, the laptop i’m typing this on has 4gb soldered + a 16gb DIMM. My question was more trying to understand why manufacturers seem to prefer using one of each rather than just making both replaceable, since the hybrid approach makes it only partly upgradeable while taking up as much physical space as if both slots used removable DIMMs. Since it seems like this combines all of the disadvantages of fully replaceable and fully soldered RAM with only half of an advantage, why are there so many laptops which do it?