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High capacity, high-performance fault-tolerant storage for photography and video.
Non-RAID or RAID-0/1/4/5/10.
Capacities up to 84 Terabytes!
iMac Fusion Drive Performance (Separate SSD / HDD)
Breaking the Fusion volume using the low-level command line 'diskutil', one can see the two drives involved, and test them independently as separate volumes. The Fusion volume consists of a 121GB SSD and a hard drive (HDD):
APPLE HDD ST1000DM003: 121.3 GB = 121332826112 bytes = 118489088 1024K blocks
APPLE SSD SM128E: 1000.2 GB = 1000204886016 bytes = 976762584 1024K blocks
In GB=1024^3 terms, the two drives are 113.0GB and 931.5GB, respectively, which explains why marketing types prefer to use base ten— 121GB sure sound better than 113GB.
Shown below is the performance of the 121.3GB SSD used in the Fusion drive, using data obtained from diglloydTools DiskTester fill-volume.
Performance is solid, but with regular glitches in writes, perhaps some kind of internal SSD housekeeping. Reads are much faster than writes.
Hard drive only
Shown below is the performance of the 1000.2GB HDD used in the Fusion drive, using data obtained from diglloydTools DiskTester fill-volume.
The hard drive averages 154MB/sec writes and 138MB/sec reads, figures that correspond quite well to the performance seen in the Fusion setup. Somehow the Fusion setup of SSD + HDD produces a result about the same as the average hard drive speed. Which is not so appealing when at partial capacity the hard drive on its own can run much faster than that.
The peculiar drive pattern for reads must speak to some sort of caching or other optimization. It is is a good thing to see such upward blips over a consistent baseline; in ordinary use it is probably quite fast for a hard drive.
Mega deal zone
$749 SAVE $400 = 34.0% Apple 12.9" iPad Pro (Mid 2017, 512GB, Wi-Fi Only, Gold) in Electronics: iPads and Tablets
$5199 SAVE $1000 = 16.0% Apple 15.4" MacBook Pro with Touch Bar (Mid 2018, Space Gray) in Computers: Apple Macs
$899 SAVE $400 = 30.0% Apple 21.5" iMac with Retina 4K Display (Mid 2017) in Computers: Apple Macs
$1049 SAVE $450 = 30.0% Apple 21.5" iMac with Retina 4K Display (Mid 2017) in Computers: Apple Macs
$7995 SAVE $3720 = 31.0% Leica Leica SL (Typ 601) Mirrorless with 50mm Lens Bundle in Cameras: Mirrorless
$350 SAVE $50 = 12.0% Samsung S32D850T 32" Widescreen LED Backlit LCD Monitor in Computers: Displays