As mentioned in my original question, the SD Association (of which Transcend are a member) cite performance impacts as a reason against using standard drive formatters.
However, they have a formatter available for download at https://www.sdcard.org/downloads/formatter_4. On Mavericks, I reformatted my drive using this utility and recopied my files.
The results were as follows:
- A single file 14.57GB took 4 minutes to copy. This is the exactly as advertised 60MB/s write speed.
- 80k files (16GB), however took 92 minutes to copy. which reflects about 5MB/s
In both cases, however, the info window was as expected showing a reasonable amount of memory usage and memory remaining. So, this solved my original problem.
As a comparison, I decided to reformat as a Journaled and found the following:
- 14.57GB file took 10 minutes to copy, which is only about 50% of the advertised max speed.
- 80k files (16GB) more importantly took only 10.5 minutes.
For me, sticking with a Journaled format is a no brainer, particularly if writing lots of small files, which I will be. It also may allow me include this on a Fusion drive, although I haven't investigated this yet.
TL;DR - It is probably best to reformat to a Journaled partition as it provides a more consistent write speed of about 30MB/s, no matter the file sizes. ExFAT ranged between 5 to 60 MB/s speeds, depending on the number of files being written (lower number is faster).
UPDATE: Transcend replied to recommended a replacement.
The latest MacBook Pro 13" (MacBookPro12,1) comes with a special internal HD interface based on PCIe and uses a special form factor for the SSD. Check the ifixit replacement guide how it looks like. This replacement guide shows a MacBook Pro 2014 but the SSD in the recent model looks similar.
So internally there is neither space nor an appropriate interface to upgrade it with HDD storage.
The last MacBook Pro 13" with a SATA interface and an HDD is the MacBookPro9,2. Check the link in the answer provided by Tuan Anh Tran where to purchase it.
Best Answer
Your best option is to get a memory expansion module. I have a 2013 Air and I purchased the PNY 128gb StorEDGE. It's very fast and would double the available storage on your Air.
As others have indicated, opening the Air to add another/bigger SSD would be more expensive and difficult than just adding an expansion module.