How to create a blazingly fast 4GB/s RAM Disk in OS X

“RAM Disks, as the name indicates, are logical storage volumes created using a computer’s memory (RAM) instead of a traditional hard drive or solid state drive,” TekRevue reports. “The benefits are easy to understand: RAM operates at speeds far beyond current hard drive technology. But there’s also a major negative: data stored in RAM is not persistent, meaning that it is erased when the RAM loses power due to a reboot, shutdown, or power loss.”

“Despite this drawback, there are still several situations that can greatly benefit from the speed of a RAM Disk, including using it as a Photoshop scratch area, manipulating large video files, or testing complicated databases,” TekRevue reports. “If you’ve got good backups of your data and you’re willing to risk losing the contents of a RAM Disk in the event of a power failure, setting one up is easy and fun.”

TekRevue reports, “The speed of RAM Disks will vary based on the performance level of your Mac’s RAM, but will still outperform traditional HDDs and SSDs by a wide margin… The OWC SSD can achieve 490MB/s writes and 540MB/s reads, numbers that by normal standards are exceptional. When compared to the performance of a RAM Disk, however, the SSD’s performance isn’t worth a second look. The RAM Disk peaks at about 4.2 gigabytes per second in both reads and writes, and averages about 3.5GB/s throughout the transfer sizes. For disk-intensive tasks, this performance can be a game changer.”

Read more in the full article here.


  1. Some of us OGs remember the ramdisk option built right into all of the early versions of MacOS. There was a button in setup. And while I’m reminiscing, let’s bring back the Scrapbook! 🙂

  2. Joke as you may, the RAM disk is crucial in extending the life of an SSD since the tmp directory is so heavily used and does not require persistentence. For this I use a ram drive on my Mac.

Reader Feedback

This site uses Akismet to reduce spam. Learn how your comment data is processed.