Thunderbolt 3 is the fastest interface available in the market today, supporting 40 Gb/s links. To best take advantage of this speed, storage companies like Seagate have loaded up on the number of drives which are accessible through a single Thunderbolt 3 link. Like having more driving lanes on a fast highway, more drives gives you higher read/write throughput on a 40 Gb/s Thunderbolt 3 link. With their LaCie brand, Seagate has released the LaCie 12big Thunderbolt 3 which offers one of the fastest read/write performance out there by giving access to twelve SATA Gen 3 (6 Gb/s) drives which can be configured in JBOD and various RAID configurations.
To get the best performance out of the LaCie 12big Thunderbolt 3, it's best to use it with high performance computers which use four PCI Express Gen 3 lanes to connect the Thunderbolt 3 port to the rest of the system. On the Touch Bar version of the Apple 13" MacBook Pro (Late 2016), the left side Thunderbolt 3 ports provide the maximum performance possible to take advantage of what the LaCie 12big Thunderbolt 3 can deliver.
A Thunderbolt 3 active cable is used to directly connect the LaCie 12big Thunderbolt 3 to one of the Mac's left-side Thunderbolt ports. With twelve 10 TB drives set up in RAID 5 mode, we use the AJA System Test performance tool to measure read/write performance while simulating a transfer of a 5K UltraHD resolution video file and a 16 GB test file size (note changing the file type and size can have a big impact on the results). Here, we record an average transfer speed of 2249 MB/sec (read) and 1123 MB/sec (write).
To see how the Mac's right-side Thunderbolt ports affect the read/write performance, we reran the same AJA benchmark tests with the same setup with the LaCie 12big Thunderbolt 3 connected to one of the right-side ports using the same active Thunderbolt 3 cable. Here we see a lower transfer speed of 1348 MB/sec (read) and 1031 MB/sec (write). The lower PCIe Express performance on the right side ports affect the read performance a lot more than the write performance.
To confirm that both the left and right-side ports are working properly, we checked for proper enumeration of Thunderbolt and PCI Express links as well as the drive showing up using disk utility.
The LaCie 12big Thunderbolt 3 connects to one of the Mac's left-side Thunderbolt port as follows:
Below shows the LaCie 12big Thunderbolt 3's enumeration using one of the Mac's right-side Thunderbolt ports:
Although the LaCie 12big Thunderbolt 3 is more geared towards professionals and avid enthusiasts with big budgets, the read/write performance witnessed on the Apple 13" MacBook Pro with Touch Bar (Late 2016) really demonstrates what Thunderbolt 3 is capable of in high multi-drive count storage solutions.