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I see microSD cards up to 400GB, as well as SSD up to 400GB.

My question is related to the size: If you can fit 400GB in a microSD card, why do we need the size of a SSD (more commonly, 2.5 in)? What other electronics or components are in a SSD that its size is so much bigger than a microSD, while having same storage?

Giacomo1968
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igorjrr
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1 Answers1

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The difference is speed.

NAND-based SSD's and flash USB drives use similar but differing technology. "One of the major differences between a modern SSD using NAND flash and a micro-SSD card that also uses NAND flash is in the way the flash is accessed. SSDs have high-speed controllers designed to read and write data... to multiple flash chips at the same time."

Now Non-Volatile Memory Express (NVMe) is yet another implementation of NAND technology that is becoming more common, with increased parallelism, enabling yet faster I/O.

There are two issues with high-speed parallel operation that cause these devices to be made larger:

  • More interconnects are needed to support simultaneous parallel operations, so more space is consumed by "wiring".
  • More heat is generated, because more operations are being performed per second, so more area is needed to remove that heat.

To accommodate these needs, currently, SSD's are in larger enclosures. As progress is made with existing devices, or as new technology is introduced (memristors? 3-D IC's? Black swans??), surely circuits will shrink, and be less power-hungry.

DrMoishe Pippik
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