📅 November 23, 2018
“400 GB on a MiscroSD card? Wow!”
MicroSD cards keep growing in capacity. The SanDisk 400GB MicroSD card packs more space than many hard drives onto a tiny wafer that a vacuum cleaner could easily swallow into oblivion.
Does this card work with Linux, and if so, what kind of performance can be expected? Here are my results.
Expecting Great Things
Like many of the items I test with Linux, I pay for them out of my own pocket. While the price was on sale at the time of purchase a few months ago, it was still more than most other cards, so this had better meet my expectations.
“Why 400GB? Who would ever use that much space on a MicroSD card?”
Rather than having several lower-capacity MicroSD cards and shuffling among them, why not use a single card that holds everything?
Besides, there is something called Parkinson’s Law of Data in the computer world where data expands to match the capacity of a storage device. This is why there will never be a hard drive with a large enough capacity.
Because of this, you can never have a MicroSD card that is “too big.”
The Card Itself
“Why 366GB? I thought this was a 400GB card?”
Subtract 7% from the capacity quoted on the box, and you will get the real, usable capacity. This is true for any hard drive or storage device. Remember the asterisks on the box? The box quotes raw capacity (with asterisks), not usable capacity.
(400 – 7% is actually 372, so 366 is reasonably close. Linux reports a higher usable FAT32 space.)
Let’s perform a quick 5x100MB test in Windows 10 using CrystalDiskMark 6.0.2.
This is a UHS-I, Class-10 card, so I was expecting a write speed of around 12-15MB/s based upon past experience with other cards. The 54MB/s is not screaming performance, but it is much better than the base Class 10 write speed.
What does Linux Mint 19 say about this card?
In all of my testing, I never reached those magical “up to 100MB/s” speeds. (That’s why the asterisks and fine print are on the box.)
Note that in all cases, the SanDisk 400GB card was connected to a USB 3 port using a USB 3 card reader in Linux Mint 19, Windows 7, and Windows 10.
This is a good card!
I have not encountered any issues that would degrade performance. No bad sectors, no read errors, no write errors. It just works. Of course, exFAT is horrible to begin with, but when formatted to FAT32, every device I tried was compatible, and the full 366GB space was accessible. This might not be true with older MicroSD devices, such as the PSP, so experimentation is necessary.
For my uses, the SanDisk 400GB MicroSD is a solid performer and provides a large capacity for future growth. If you are need of a reliable MicroSD card with plenty of storage space, then this item is certainly one to consider.
Best of all, it works with Linux!