May 27, 2020.
Blackmagic is now faster enough to rate internal SSD speeds, even the Startup Disk
Blackmagic has been updated to adequately report the speed of SSD devices.When Blackmagic tries to read the Startup Disk, you get the message that the device is not writeable, hence you cannot rate the the transfer rates of the drive.I found a workaround that will report the rates of the Startup Disk. Its quite simple. Create a disk image (.dmg) using the disk utility specifying file->new image->blank image. Make it big enough for Blackmagic to work with (7+ GB) and name it what you will. Mount the volume (if it is not already mounted).In Blackmagic select the disk image mounted. Since the “volume” is on your Startup Disk, you will see how fast it drive is. On my 2016 MacBook Pro, I am seeing speeds like 1,000+ MB/s write, and 1100+ MB/S read. I have tried this on my older mackbooks with SSD and they do scale down as the device is older. On an older MacBook Pro the rates I see are 500 MB/S both read and write, as you would expect.I have run Blackmagic on USB 2, thumb drives, USB 3, and USB C devices to see if I’m getting my money’s worth. You can easily detect when a device is performing subpar and, and with the spinning disk, you can see is transfer speeds deteriorates over time.
