Comparison Synology DiskStation DS918+ vs Synology DiskStation DS418

Number of M.2 slots provided in the design of the NAS server.

M.2 slot is used for connecting various internal peripheral devices, mainly of a miniature form factor. This solution allows reducing the size of the NAS server itself. Solutions without 2.5" and 3.5" slots can make it compact. It is worth noting that this slot can implement two electrical (logical) interfaces — SATA 3.0 and PCI-Express, with each individual M.2 socket on the board being able to support either both interfaces simultaneously or just one of them. These details should be clarified before purchase, as they directly affect the capabilities of using M.2. For instance, with SATA 3.0 support, such a slot has a significantly lower speed compared to PCI-E; therefore, this M.2 variant is mainly used for inexpensive SSD modules. In turn, PCI-E is somewhat more expensive but provides maximum data transfer speed and allows connecting high-class solid-state drives to the NAS server.

The number of eSATA connectors provided in the design of the NAS server.

eSATA is a specialized interface for connecting external drives, primarily hard drives. It provides data transfer rates up to 2.4 Gbps — half that of USB 3.2 gen1, but significantly more than USB 2.0. And the clear advantage of such an interface is that it allows you to leave free USB ports that may be required for other devices. At the same time, eSATA drives are not very common nowadays, therefore, connectors of this type are provided in NAS servers quite rarely (and mostly in an amount of less than one).

The model and specifications of the processor installed in the NAS server. The speed of the device largely depends on these characteristics, primarily the clock frequency. However, in fact, this parameter is often more of a reference value: simple everyday tasks (say, FTP and print servers, see "Software Features") do not require high computing power. But for working with extensive databases (see ibid.), a “faster” processor may be useful.

Clock speed of the processor installed in the NAS server.

The clock frequency is the frequency of the built-in oscillator, according to which all operations performed by the processor are synchronized. The higher this frequency, the more operations per second the CPU can perform and the easier it is to provide high computing power in it. However, note that the actual speed of the processor depends on many other features — the number of cores (see above), microarchitecture, volumes of the built-in cache memory, etc. So, only chips with similar characteristics and purpose can be directly compared by clock frequency ( desktop/mobile) and price category.

Processor clock speed achieved in TurboBoost or TurboCore "overclocking" mode.

Turbo Boost and Turbo Core technologies are used by different manufacturers (Intel and AMD, respectively), but they have the same principle of operation: load distribution from more loaded processor cores to less loaded ones to improve performance. The "overclocking" mode is characterized by an increased clock frequency, and it is indicated in this case.

For more information about clock speed in general, see the relevant paragraph above.

The amount of RAM on the NAS server. Along with the processor, it is one of the indicators that determine the speed of the system — the more memory, the higher the computing power. However, in fact, it does not always make sense to chase large amounts of "RAM", which can reach 4 GB, 8 GB and even higher; see "Processor" for details.

The maximum amount of RAM that can be installed on the NAS server. It depends, in particular, on the type of memory modules used, as well as on the number of slots for them.

The total number of slots for RAM modules provided in the device; in fact — the maximum number of slats that can be installed simultaneously in this model.

Features for upgrading RAM directly depend on this indicator. So, in low-cost models, there is often only 1 slot, and the only upgrade option is to replace the “native” bar. In more advanced devices, two or even four slots may be provided, while some of them may be free in the initial configuration.

The amount of power consumed by the NAS server during normal operation. Most often, we are talking about maximum power consumption — with all the occupied slots for drives, under high load.

Modern NAS, even high-performance ones, have rather modest power consumption — even among professional models with 10 or more drives, this figure rarely exceeds 1 kW. So there are no problems with connecting to a 230 V network. However, energy consumption information can be useful for some special applications, primarily for estimating the load on UPSs, emergency generators, stabilizers, and other special equipment.