SHOOTOUT: iMac Retina 5K
Flash Storage versus Fusion Drive
Posted Thursday, October 23 2014 by rob-ART morgan, mad scientist
Updated October 31st with 1TB and 3TB Fusion Drives.
The iMac with Retina 5K Display can be ordered with either Fusion Drive or Flash Blade. Our unit was ordered with the 1TB Flash Storage. We benchmarked it against the 'late 2013' iMac with 512G Flash Storage and the 'late 2013' Mac Pro with 512G Flash Storage. (As of October 31st, we added two examples of the latest Fusion Drives that the factory ships with the 'late 2014' iMac 5K.)
2013 nMP 512G Flash = 'late 2013' Mac Pro 3.7GHz Quad-Core Xeon; 512G Flash Storage
2014 iMac 1TB Flash = 'late 2014' iMac Retina 5K 4.0GHz Quad-Core i7; 1TB Flash Storage
2013 iMac 512G Flash = 'late 2013' iMac 3.5GHz Quad-Core i7; 512G Flash Storage
2014 iMac 3TB Fusion = 'late 2014' iMac Retina 5K 4.0GHz Quad-Core i7; 3TB Fusion Drive
2014 iMac 1TB Fusion = 'late 2014' iMac Retina 5K 3.5GHz Quad-Core i5; 1TB Fusion Drive
LARGE SEQUENTIAL TRANSFER TEST
We used AJA System Test to test file level sequential transfer speed using a 16GB test document.
SMALL RANDOM TRANSFER TEST
We used the range of 4K to 1024K blocks in the Standard Random test of QuickBench as a predictor boot volume 'house keeping' performance and a simulation of an application that does multiple small random transfers.
The 'late 2014' iMac 5K's Flash Storage is somewhat of a disappointment since it is no faster than the 'late 2013' iMac's Flash Storage. We were hoping transfer speeds closer to the 'late 2013' Mac Pro (and 'mid 2014' Retina MacBook Pro).
"Light Bulb!" We now know why the iMac's Flash Storage is slower than the Mac Pro's (even though they have the same Samsung based XP941 blade). The iMac's flash storage is running at a PCIe link width of x2 while the Mac Pro's storage is running at a PCIe link width of x4.
You can take comfort, however, in the fact that if you connect a fast Flash Storage device to the Thunderbolt 2.0 port, you will see transfer speeds closer to the 'late 2013' Mac Pro. For example, the OWC Helios 2 PCIe Expansion Box with a Samsung 512G XP941 Flash Blade recorded large sequential transfer speeds of 1214MB/s when we connected it to our 'late 2014' iMac 5K. You will get even faster speeds with the LaCie Little Big Disk Thunderbolt 2.0.
OUR OTHER iMAC 5K PAGES
Go to our INDEX page for a list of several pages featuring the iMac with Retina 5K Display compared to other Macs.
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