Comparison Ugreen CM400 vs AgeStar 3UBNF5C

General purpose of the pocket.

Note that different types of such accessories (see above) are divided according to their purpose. External pockets are categorized as portable and stationary, while internal ones are divided into models for laptops, for PC chassis, and solutions for servers. This parameter is generally not specified for docking stations and cases: the former are originally intended for stationary use, while the latter, by definition, are portable.

Here's a more detailed description of the options relevant for external pockets:

— Portable. Models designed for frequent movement from place to place and even for use on the go (for example, connecting to a laptop while traveling). Most modern external pockets fall into this category, as external storage devices, which these pockets are an alternative to, are mainly made portable. The specific features of such accessories can vary, but they are all compact enough and designed for only one internal drive, receiving power from the same USB port they connect to (see "Power").

— Stationary. External pockets intended to remain in one place and not meant for frequent relocations or use on the go. These models are significantly less common than portable ones; most of them are fairly large constructions designed to...hold two or more drives and often represent a kind of "NAS servers without network functions." However, there are single-slot models that differ from portable counterparts by having a stand to position the pocket vertically (saving space on a desk), and powered by a PSU.

In turn, internal pockets for different purposes have the following specifics:

— For laptops. This variety is usually designed for installing drives of the 2.5" or M.2 form factor into the optical drive bay (CD/DVD) — due to the compact size of laptops, this is often the only possible way to install an additional drive.

— Chassis. Pockets intended for standard desktop PCs. Note that the term "chassis" traditionally refers to a specific variety of such pockets — known as Mobile Rack, or "sleds". The main purpose of these accessories is to allow quick transfer of drives from one enclosure to another. Their construction includes two parts: a base that mounts in a 5.25" slot on the case, and a removable cartridge where the drive is installed. To prevent theft or unauthorized physical access, "sleds" can be equipped with a lock that blocks the removal of the drive. Such devices are quite rare today, mostly used with disk arrays and in certain specific circumstances — for example, to take a drive containing materials with you at the end of the workday or to lock it in a safe for confidentiality. Another type of pockets for PCs is adapters for installing drives in non-standard slots. A classic case is using a 2.5" "laptop-sized" drive in a 3.5" bay of a desktop case, but nowadays a more specific variant can be found — using an M.2 SSD as a PCI-E expansion card (see "Form factor" for more details).

— For server. Server systems often deal with large volumes of information that require high reliability and/or access speed. In light of this, most pockets for this purpose are designed for multiple drives (from two to six), allowing for necessary volumes and RAID arrays of different levels if needed. Built-in RAID support (see below) is not found in such devices — it's simpler and more sensible to organize it through the server itself. It's also worth noting that these pockets, by the way to install disks, are usually "sleds" (see "Chassis" above), providing added convenience, allowing, for example, quick swapping of a failed drive in a RAID array. Server pockets may use specialized interfaces like SAS, although traditional SATA is more popular.

The method of connecting a pocket with an installed drive to a computer as provided in the design.

Note that this parameter is specified only in cases where the interface for connecting differs from the interface of the drive (see above). This feature is typical for all external models and docks (see "Type"): nowadays they most frequently use USB-A 5Gbps, less often — USB-A 2.0 or USB-C of various versions (see below). In internal solutions, the drive's connector is very rarely different from the pocket's connector, although exceptions occur.

It is also worth mentioning that in external models the connection method is usually determined by the type of complete cable; such a cable is often made detachable, with the possibility to replace it with a "cord" with a different type of plug.

As for specific connection methods, here are their main features:

— USB-A 2.0. USB is used for connecting external peripherals, including pockets; this is the most popular modern interface for such purposes. Version 2.0 is the oldest USB standard still current today. The capabilities of such a connection are rather modest — for instance, the power capacity through the connector is 2.5 W, and the maximum data transfer speed does not exceed 480 Mbps. This is noticeably slower than even SATA 2 (3 Gbps), let alone SATA 3 (6 Gbps); thus this standard is gene...rally considered obsolete, and in pockets with this type of connection, the overall performance is limited to the capabilities of USB-A 2.0. Nevertheless, supporting this interface is inexpensive; for simple tasks that don't involve large amounts of data, it often proves to be quite enough; moreover, USB 2.0 devices are fully compatible with USB ports of newer versions. Thus, today you can still find pockets with this type of connection — mainly the simplest and cheapest models.

— USB-A 5Gbps. This version (previously known as USB 3.2 gen1 and USB 3.0) is the direct successor of USB-A 2.0, providing data transfer speeds 10 times higher — up to 4.8 Gbps — and higher power capacity. The mentioned speed practically matches the capabilities of the popular internal SATA 3 interface; therefore, pockets with this type of connection are extremely widespread today.

— USB-A 10Gbps. Connection to a computer through a full-size USB connector, supporting data transfer speeds up to 10 Gbps. This version is particularly useful for fast SSDs, where a higher-speed interface helps better utilize the drive's capabilities. Compared to USB-A 5Gbps, this variant is more attractive for copying large files, working with video archives, and backups, where not just compatibility but also higher data exchange speed is important. For regular HDDs, the difference may also be present, but the effect is often more modest because the hard drive is usually slower than an SSD.

— USB-C 5Gbps. Modern USB-C connector with data transfer up to 5 Gbps. This option is suitable for regular external SSDs and HDDs, when convenient connection and normal speed for daily tasks are important. Compared to USB-C 10Gbps, it's a more basic option, but for many drives, it is already quite sufficient.

— USB-C 10Gbps. High-speed USB-C interface with data transfer up to 10 Gbps. This option is especially interesting for fast SSDs, where a higher speed cap helps better leverage the drive's capabilities. Compared to USB-C 5Gbps, it is more suited for large video projects, massive archives, frequent copying of heavy files, and using the drive almost like an external working disk. For regular HDDs, the difference is often less noticeable because the hard drive is usually slower than an SSD.

— USB-C 20Gbps. The fastest USB-C option in this line, designed for data transfer up to 20 Gbps. This format is especially interesting for fast SSDs when the pocket is used not just as an external storage, but almost like a full-fledged working disk for large projects, editing, archives, and regular copying of heavy files. It is essential to ensure that a compatible port and cable are available for such speed. Thus, USB-C 20Gbps is an option for those who want to get the most out of an external SSD and not be limited by the interface too soon.

— PCI-E. Connection to a standard PCI-E slot on the motherboard. In other words, such pockets connect to the computer in the same way as video adapters, sound cards, and other expansion cards. This design is used in specific internal models for M.2 SSD form factor drives; such a pocket allows connecting a similar drive to a desktop PC even if the native M.2 ports on the motherboard are occupied, unavailable, incompatible for connection (for example, using the SATA interface while the drive is made for PCI-E), or completely absent.
Note that these pockets are usually compatible with SSD modules on M.2 PCI-E without issues, but compatibility with M.2 SATA should be clarified separately (though such functionality does exist). It should also be noted that PCI-E slots and devices under them can have a different number of lanes, and the general rule here is: the number of lanes of the slot on the motherboard should be at least as many as the card being connected. However, pockets with such connections usually provide no more than 4 lanes, so they can be connected to PCI-E slots starting from 4x.

— IDE. An outdated interface for connecting internal drives. It is extremely rarely encountered in modern pockets — only in certain models designed for installing modern HDDs/SSDs in outdated computers without SATA and other current connectors.

The number of separate slots for drives provided in the design of the pocket, in other words, the number of drives for which this model is designed.

In addition to models for one slot, nowadays you can find more capacious solutions — for two drives, or even more. Such "multiplying" is found in three types of devices. The first is large-format pockets for stationary purposes (see above), operating in the format of separate storages for a large amount of data. Such models may support RAID arrays (see above) and other special features. The second type of devices with more than one slot are separate docking stations (see "Type") with similar functionality. The third type is server models (see "Purpose") with an internal installation; they again allow the organization of arrays, but by means of the server itself.

Note that external devices with one slot can be powered from the USB port, but several drives in this case inevitably require a separate PSU (see "Power").

The maximum storage capacity supported by the pocket. In models with multiple disks/SSDs (see "Drive Slots"), this item indicates the largest total volume supported by the device; by dividing this capacity by the number of slots, you can determine the maximum allowable capacity of each individual drive.

The limitation on the maximum volume is relevant mainly for external models, including docking stations (see "Type"). This is due to the fact that fundamentally different interfaces are used for the drive and for connecting the pocket itself in such models (most often SATA and USB, respectively, see above for details). For the normal interaction of such interfaces, an electronic controller is required; and the larger the volume of the installed drive (s) — the higher the requirements for the performance of such a controller.

Note that, other things being equal, supporting large volumes is more expensive, and capacious drives themselves are not cheap. Therefore, when choosing according to this indicator, it is worth considering real needs, and not chasing the maximum numbers.