Transcend JetDrive Lite 350

Transcend's JetDrive Lite expansion , around a third of the size of an SD cards, these MLC flash (a type of NAND memory) cards can boost a 13- or 15-inch MacBook Pro's storage capacity by slotting into its SD card slot. Unlike regular SD cards that stick out of the side, Transcend's offerings can be fully inserted to the point where the card is practically indistinguishable to the machine's edge.

Available in 64GB (£31, around $64 or AUS$84) or 128GB (£64, around $89, or AUS$ 101) capacities, they don't offer anywhere near the storage of external hard disk drives or SSDs, but they have the advantage of being super portable and much cheaper. And because the card doesn't stick out of the machine, there's less chance of it being broken while being transported.

The card shows 128.68GB remaining out of a possible 128.67GB in OS X, with 9MB remaining on the card, meaning you get close to the advertised capacity and then some. To benchmark it, we used Blackmagic Disk Speed Test running on OS X 10.9 Mavericks, which benchmarks the disk by writing large blocks of data to disk and then erasing it provide a performance reading.

Transcend claims that both its 64GB and 128GB models have a maximum read speed of 95MB/s and maximum write speed of 60MB/s, and we found that our review card came pretty close. However, its write speeds proved inconsistent, fluctuating from a low of 20MB/s to a high of 55MB/s.

Read speeds were more consistent, frequently reaching between 70MB/s and 80MB/s, topping out at 87.1MB/s. While that's not going to match the speed of even the slowest modern SSDs, it's a decent speed for the kinds of tasks the card has been designed for, which is storing and viewing multimedia files such as videos, music and pictures.