USB 3 can range anywhere between 100 MB/sec to the theoretical maximum of 640 MB/sec.

However, USB 3 can burst up to 640 MB/sec, so while my 10 MB/sec Micro SD card is guaranteed to be at least 10 times slower – it could be 64 times slower… Since my U1 Micro SD card is 10 MB/sec, and USB 3 was a minimum of 100 MB/sec, I already know that this is going to be at least ten times slower. Now that we know that my new U1 Micro SD card is going to operate at 10 MegaBytes per second, let’s compare this to the SanDisk USB drive I was using before… That used “USB 3” (yes, there is a difference between USB and USB 3 – USB 3 is loads faster). When you see 100 M Bps or 100 MB/s, that means Mega Bytes per second, or 8 times faster.

It is worth noting, when looking at these speed levels, the difference between the lowercase “b” and the uppercase “B”. When you see 100 M bps, that means Mega bits per second. Here is a table that shows the different speeds of SD cards, taken from along with all the logos you will see on the SD card and it’s packaging:Īs it turns out, it wasn’t as fast as it was going to get, since I got a U1 Micro SD card which is 1/3 as fast as the U3 Micro SD card. My Micro SD card is what is called a “U1” card. I started researching Micro SD cards and their speed, but quickly had to just say, “Well, this is probably as fast as it is going to get”.

I’m using this BASEQI adapter and this PNY 128GB card and it looks like this: This article is where I will be documenting my use of a Micro SD card to store Dropbox content. I’m using an adapter that takes a Micro SD card and allows you to stick it into your MacBook’s SD card slot and sit flush with the edge. Over the last year, I’ve been trying several methods in the hopes of finding the perfect solution. A little over a year ago, I wrote an article that documented how I was using an external drive with Dropbox.

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