The EXOS drive beats the IronWolf Pro with a workload limit of 550TB, a significant improvement over the 300TB of its brother mechanism. These are the same workload limits as the Western Digital UltraStar DC HC560 20TB and WD Gold 20TB. Still, while external SSDs are cheaper than they were a few years ago (see the best we've tested at the preceding link), they're far from a complete replacement for spinning drives. Larger external drives designed to stay on your desk or in a server closet still almost exclusively use spinning-drive mechanisms, taking advantage of platter drives' much higher capacities and much lower prices compared with SSDs.

How an external drive connects to your PC or Mac is second only to the type of storage mechanism it uses in determining how fast you'll be able to access data. These connection types are ever in flux, but these days, most external hard drives use a flavor of USB, or in rare cases, Thunderbolt.

An Enterprise-class 20TB NAS drive

The LaCie 2big RAID array promises the reliability and delivers the performance benefit you'd expect from 7,200rpm platters, magnified by the default RAID 0 setting, while the optional RAID 1 setting is available if you want data redundancy. (A JBOD mode is also available if you don't want to use RAID.) Who It's For The most common use for hard drives, though, is simple file transfers. Our DiskBench test estimates transfer performance with a real-world workload that is useful for calculating how long a transfer could take. Hard drives have consistent performance and will hit their maximum sustained speed at QD1 with large enough I/O, which is illustrated in our ATTO benchmark results. This is particularly useful for showing differences in technology and capacity as drives get bigger and faster. U.2 also allows you to install multiple SSD drives on workstation mobo. Which of course you can't do with consumer M.2 mobo, because you would end up with a giant mobo.U.3 to the rescue, replace the SATA ports on the right edge of the MoBo with U.3. Additionally, the number of bits a cell contains serves as one of the primary ways to classify NAND Flash: Many years of close collaboration work with our key component suppliers is leading to impactful technology breakthroughs to achieve higher capacities, which ultimately reduces total cost of ownership (TCO) of our nearline HDDs.”

PlaneInTheSky said:There are U.2 ports on some mobo, but it's mostly servers and high-end workstations that use it.U.3 should be the "Universal Standard" that replaces SATA/SAS/nVME over PCIe. Solid-state drives (SSDs) have fewer moving parts than traditional hard drives, and they offer the speediest access to your data. Unlike a conventional disk-based hard drive, which stores data on a spinning platter or platters accessed by a moving magnetic head, an SSD uses a collection of flash cells—similar to the ones that make up a computer's RAM—to save data. Evidently, both Seagate and Western Digital did the calculations and came to the same conclusion about these devices and how much use they are likely to handle before they need replacing. Quadruple-Level Cell (QLC): Similarly to TLC, QLC is also commonly found in consumer grade products. QLC stores 4-bits per cell and can take up to 16 levels of charge. Among the 4 variants listed, it has the highest memory density and cheapest price. However, the lower price comes at a cost in performance, reliability and endurance (up to 1K P/E).For the customer, the choice is between the biggest drives available, allowing the largest possible arrays, or spreading the workload between less expensive drives with potentially increased levels of redundancy. I feel like I'm in the dark ages when installing or switching out an M.2 SSD that requires a screwdriver.