The SSD Guy often hears people ask: “When will SSD prices drop below the prices of HDDs?”
This makes a lot of sense. After all, NAND flash, which makes up the bulk of the cost of an SSD is renowned for its rapidly-falling prices.
The short answer to this question is: “Never!”
Although NAND flash prices are indeed dropping at an amazing rate, HDD capacities are increasing at a similarly amazing rate. Given that the typical high-volume HDD sells for a relatively static $50 it’s easy to derive an average cost per gigabyte for HDDs and plot that against the price per gigabyte of NAND flash, which is exactly what we did in the graphic for this post.
This chart, assembled with data provided by PriceG2, an HDD and SSD price tracking service, plots average NAND and HDD price per gigabyte from 2004 to 2011. It originally appeared in the Objective Analysis report – How PC NAND Will Undermine DRAM – which can be ordered directly from the Objective Analysis website.
The chart uses a semi-logarithmic format, in which constant growth appears as a straight line.
Note that the HDD (black) and NAND (red) lines are roughly parallel. This translates to a 20:1 price difference between NAND and HDD over the entire 7-year course of this chart. There is no reason to anticipate any dramatic changes in the future. The lines should not converge, and SSDs will always command a higher price than HDDs.
I can’t seem to view any higher-resolution image of that graph. Regardless, there are a lot of unsubstantiated claims in this article. You’re looking at a trend and just assuming it will continue this way *forever*.
That’s silly. Eventually, we’ll hit physical limitations on both processes that just aren’t bypassable. Maybe not this decade, but almost certainly this century (at least for the flash case, as we approach flash cells that are barely atoms thick). When this happens, it makes sense that the graph would eventually flat-line, though which one is on bottom isn’t immediately obvious to me.
Physically, flash memory is more dense at the moment – it uses less raw material per byte. This translates to lower costs associated with shipping and stocking. Furthermore, the spinning hard disk has extra mechanical components which have themselves bottomed out to some non-zero price (e.g. a few dollars for the motor, arm and enclosure). On the other hand, the base cost of an integrated circuit is pennies (Microchip.com’s cheapest flash chip is $0.31/piece).
So if per-byte storage is trending towards 0 for both SSDs and HDDs, then in theory, the SSD will eventually become the cheaper system because of its lower base cost.
Even if per-byte storage doesn’t quite approach 0, SSDs will still become cheaper than HDDs for pretty much every consumer system. Think about it: a 1 GB flash chip certainly costs less than a 1 GB HDD today (or, rather, the lowest capacity HDD you can possibly find), and you can solder the former straight to a motherboard whereas the latter requires more expensive housing. Eventually, it’ll be the same case for 1 TB, and then 10 TB. Very few consumers even want more than that.
Colin, you are quite right. As Gordon Moore said: “Nothing is forever!”
Of course, we have only had electronic computers for about 70 years, and hard drives for 60. Memory chips are less than 50 years old. We can’t imagine what we will have by the end of this century, as you say.
I’m not sure I understand the rest of your argument. You argue that flash is denser than HDD, but flash contains far more bits per square inch than magnetic tape, yet tape is a few orders of magnitude cheaper than flash, even though it uses more raw material per byte. As for flash having a lower base cost than HDDs, to be quite honest, the cost is higher for the same amount of storage, ten or more times as much.
Interestingly enough, the Microchip part you refer to isn’t even NAND flash – it’s NOR. NOR has a significantly higher cost structure than NAND. It’s never a good idea to compare a low density chip to a higher density one, though, just as you can’t reasonably compare low-density SSDs to a high-density HDD. You’ll find a discussion about this here: https://thessdguy.com/sandisk-ssd-at-hdd-prices/
Thanks for the comment. I hope this helps clarify a few points.