UHS class
UHS bus version supported by the memory card.
UHS is a data exchange technology used in SD/microSD cards of the (micro)SD HC and (micro)SD XC standards. It allows you to significantly increase the speed of data exchange compared to previous standards; at the same time, media supporting this technology are quite compatible with equipment that does not have UHS - except that the speeds in such cases will be limited by the capabilities of the card reader, and not the card itself.
As for the versions, their names consist of two parts: UHS generation (I or II) and class (1 or 3) - for example,
UHS-I Class 1. Actually, this is the most modest version of UHS found in modern memory cards; in addition to it,
UHS-I Class 3 and
UHS-II Class 3 are popular. The maximum data transfer speed (usually referring to read mode) depends on the UHS generation - it is 104 MB/s for version I and 312 MB/s for version 2. “Class”, in turn, determines the lowest (guaranteed) write speed : it is at least 10 MB/s for Class 1 and at least 30 MB/s for Class 3. Different versions of UHS are quite compatible with each other, except that the speed in such cases will be limited by the slower standard.
Note that for UHS cards, more advanced characteristics may be indicated in other paragraphs - for example, the video recording class (see below) V90 for a UHS-II Class 3 card. There
...is no contradiction here: the speed of 90 MB/s provided by such a card in recording mode, it fully satisfies the “not lower than 30 MB/s” condition provided for UHS Class 3.Application class
Speed class when working with applications to which the memory card corresponds.
When working with applications that use a memory card (for example, mobile games), information is written and read not in a continuous stream, as when recording video or copying data, but in separate small fragments, and from random areas in the drive’s memory (the so-called random write/read). So a high-class video recording (see above) does not always mean good flow Rate when working with demanding games and other resource-intensive programs. Therefore, the characteristics of memory cards began to separately indicate the speed class for applications.
The key indicator for assigning a particular class is the minimum number of IOPS (input/output operations per second) that the media can provide in random write and read mode. Nowadays, the following classes are relevant:
—
A1 — at least 1500 IOPS for reading and 500 IOPS for writing;
—
A2 — at least 4000 IOPS and 2000 IOPS, respectively.
The continuous recording speed (for example, when recording video) in both cases must be at least 10 MB/s (often it is higher - see “Speed class”, “Video recording class”).
In the future, we can expect the emergence of new, more productive classes for applications. We also note that this parameter significantly affects the price of the card.
Speed value
The coefficient describing the maximum speed of the card in read mode. In this case, 150 KB/s is taken as a unit; thus, for example, the speed value of 533x corresponds to 150*533=79,950 KB/s, i.e. about 80 MB/s.
In general, this parameter is quite specific; in practice, it is easier to focus on the directly declared reading speed (see below). However, sometimes it is not specified - in such cases, the speed value will be most useful.
Read speed
The maximum speed of reading data from a memory card.
Any modern memory card provides sufficient reading speed for simple everyday tasks — like copying photos from a camera to a laptop. Therefore, it makes sense to pay attention to this parameter mainly in cases where the card is purchased for professional use, or if high speed is critical for you — for example, if you often have to copy photos from the camera in a hurry. In doing so, two points should be taken into account. Firstly, the corresponding speed must be supported by the card reader where the card is used. Secondly, this paragraph indicates the theoretical maximum — in perfect conditions; the actual reading speed may be lower (if we are talking about cards with UHS, this speed can be estimated by the UHS class, see above about it). Nevertheless, it is quite possible to compare different models of cards by this indicator: differences in theoretical speed usually quite correspond to the difference in actual speed.
Write speed
The maximum speed for writing data to a memory card.
High write speed is important for tasks that involve storing large amounts of data in a limited amount of time. However, note that this paragraph indicates the theoretical maximum speed for perfect conditions; in fact, this value can be noticeably lower. Therefore, the characteristics of memory cards also indicate the minimum guaranteed write speeds in different modes — the general speed class, the UHS class, the video recording class and/or the class for applications. All of them are described in more detail above. However, you can also evaluate the capabilities of the carrier by the overall speed: other things being equal, a card with a higher theoretical speed will work faster in fact.
As for specific values, speeds
from 4 MB / s and
from 6 MB / s are practically not found nowadays,
from 10 MB / s and from
16 MB / s can be called average indicators,
from 50 MB / s — above average, and the fastest models have a maximum write speed of
100 Mbps or more.
Adapter included
An additional
adapter is included with the memory card.
The adapter is a device with which the card can be installed in a non-native format card reader. Nowadays, microSD cards are mainly equipped with such a device — adapters are designed to install such media in a slot for a full-size SD card. This is convenient primarily for exchanging data between portable gadgets like a smartphone / tablet and larger equipment like PCs and laptops — for example, to copy pictures from a smartphone camera to a computer or music from a computer to a smartphone.
Card reader included
The presence
of its own card reader in the delivery set of the card.
Such a card reader is usually a miniature memory card reader connected to a computer via a USB port. When installed in such a device, the card actually turns into a USB flash drive and can be used even on those computers where there are no card readers — a free USB connector is enough.
Manufacturer's warranty
Manufacturer's warranty provided for this model.
In fact, this is the minimum service life promised by the manufacturer, provided that the operating rules are followed. Most often, the actual service life of the device turns out to be significantly longer than the guaranteed one. But an indicator of 5 years suggests that the memory card is more likely to be lost or become irrelevant. You can also find
a lifetime warranty, but in this case it is better to clarify the details of what it covers. And in any case, it implies a certain period of time, although measured in decades. In addition to confirmation of reliability, such a guarantee allows you to contact the supplier after a while to eliminate possible problems (not mechanical, of course). But the difficulties in carrying out this procedure (representative offices are located only in large cities) and the rare cases of need for this (after all, it is easier to buy a new flash drive, with the exception of vital information on the old media) make the lifetime warranty more of a marketing ploy than a cool feature.
