I have a retina MBP (MacBook Pro (Retina, 15-inch, Mid 2014)) with an SSD of 256GB. Using it for a month or 2 now, I'm noticing that I'd like some more space (for using a Virtual Machine). There isn't yet a way to upgrade the interal drive, and I've been wondering what the more efficient upgrade is:

  • Transcend Jetdrive Lite (Claims Read speed of 95MB/s, Write 60MB/s)
  • USB3 memory stick (Bigger in physical size, smaller in disk space)
  • External USB3 SSD / HDD (Which is what I'd least like in physical size)

The ideal "upgrade" would be small size, so I can leave it in and forget about it, but fast enough to use for my Virtual Machines (and big enough).

Being a Windows developer I need to run full blown VMs. Currently I have 2 VMs on my SSD, both of which use the storage quite a lot (a server and a compile machine). I'd now like to use another VM, mostly to use as a thin-client to connect to customers' servers. This means that the third VM (the one on the extra storage) doesn't need to be as fast as an SSD, nor does it need to be as big. I think it currently sits at around 30-40GB.

Currently I do not know what kind of read / write speeds are enough for my thin-client VM, because it's more of a 'i'll know it when i see it' problem.

Does anyone have benchmarks or advice on how to proceed?

  • You can most certainly replace the internal SSD with a larger one. I upgraded a newer MacBook Pro to a 500GB SSD (Samsung EVO 750) and it was quite easy. Don't bother with the first two options you listed, if you aren't going to upgrade the internal, go with an external SSD via USB3 or Thunderbolt.
    – Pixelwiz
    Commented Apr 7, 2015 at 20:08
  • I called to the shop I bought it from (apple reseller) today, and they told me there wasn't an upgrade available for this machine (MacBookPro11,2) just yet. Commented Apr 7, 2015 at 20:34
  • Officially, that's correct, they won't support replacing the SSD in a Late 2014 or Early 2015 MBP. It's a PCI 2.0 (x4) SSD, but you'd be on your own doing the replacement, and voiding any existing warranty.
    – Pixelwiz
    Commented Apr 7, 2015 at 20:43
  • if you need all the files on the external at all times then transcend jetdrive lite will be the easiest to carry around. if you have a lot of movies/music that you dont particularly need on the go then get a good external drive and put them there. and yes you cannot upgrade the SSD of 2014 and 2015 rMBP as they have a different connector than the commercial ssd you can buy in store, only way to upgrade these machines are through apple and they will charge more than the common SSD price
    – tom
    Commented Apr 7, 2015 at 22:02
  • I don't really want to void my warranty though.. Commented Apr 8, 2015 at 15:00

2 Answers 2


A traditional USB flash stick will not cut it for your purposes. This is not a question of R/W speed. Regardless of the R/W speeds (I own an excellent 128GB PNY Turbo stick), the on-board controller (the microchip that serves as the brains behind the drive’s operation) is built for low-cycle I/O operations. If you plan to run virtualization software from an external drive, with portability/size being the caveat, your best bet is purchasing an mSATA-based SSD with an exclosure.

Here’s a good image to put the size into perspective:

enter image description here

Bottom line: you won’t be able to reliably run a VM from a USB based flash drive. You need a dedicated external drive with a controller engineered to handle the operations you plan to execute.


I'll go for the MBP SSD replacement because it'll not void any Apple warranty (as written in this thread and the last link to Apple warranty).

In my case I'm working with a Samsung SSD 850 Pro 256GB and an external WD HD 500GB 5200rpm for Windows VMs. I'm using VMware Fusion and I'm not experiencing any kind of slow down or lag spike.

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