UHS class
UHS bus version supported by the memory card.
UHS is a communication 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 is quite compatible with equipment that does not have UHS — except that speeds in such cases will be limited by the capabilities of the card reader, and not by the card itself.
As for 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 UHS generation determines the maximum data transfer rate (usually meaning read mode) — 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 a slower standard.
Note that for UHS cards, other paragraphs may also indicate more advanced characteristics — for example, the video recording class (see below) V90 for a UHS-II Class 3 card. There are no
...contradictions here: the speed of 90 MB / s provided by such a card in write mode, fully satisfies the “at least 30 MB / s” condition provided for UHS Class 3.Video recording class
The video recording class supported by the memory card.
This parameter is specified for SD/microSD cards and their variations, as well as CompactFlash (see "Type"). In the first case, the V* format designation is used, in the second, VPG*, but the idea is the same there and there: the numbers indicated instead of an asterisk are the lowest write speed (in MB / s) that the card is guaranteed to provide. This speed is of key importance primarily in video shooting, which is why this parameter is called “Video Recording Class”; the higher it is, the higher the resolution and frame rate at which you can record using this card.
The minimum video recording class found in modern cards of the SD / microSD family is
V6, it already allows you to work with HD and Full HD video. However, for Full HD it is desirable to have a card of at least
V10 level. And the
V30 class already allows you to comfortably work with Ultra HD 4K. Faster cards are also being released — V60 and even V90, suitable already for 8K resolutions and higher.
In turn, in CompactFlash cards you can find models of classes
VPG20,
VPG65 and
VPG130
Note that the video recording class may well be higher than the general speed class and/or UHS class (see above). However, there are no
...contradictions here. The requirements for the UHS class provide a write speed "not lower than ..."; thus, for example, all cards with a video recording class of V30 and higher will comply with the UHS Class 3 standard (“at least 30 MB / s”). And the general speed class describes the card's capabilities when working with equipment without UHS support (and such equipment is practically not used in video recording).Application class
The application speed class that the memory card corresponds to.
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, moreover, from random sections in the memory of the drive (the so-called random write / read). So a high video recording class (see above) does not always mean good performance when working with demanding games and other resource-intensive programs. Therefore, in the characteristics of memory cards, they began to separately indicate the speed class for applications.
The key indicator for assigning one or another class is the minimum number of IOPS (input / output operations per second) that the media can provide in random write and read mode. The following classes are relevant today:
—
A1 — at least 1500 IOPS for reading and 500 IOPS for writing;
—
A2 — at least 4000 IOPS and 2000 IOPS, respectively.
The speed of continuous recording (for example, when shooting video) in both cases must be at least 10 MB / s (often it turns out to be even more — see “Speed class”, “Video recording class”).
In the future, we can expect the appearance of new, more performant classes for applications. Also note that this parameter significantly affects the price of the card.
Speed value
Factor describing the maximum speed of the card in read mode. In this case, 150 KB / s is taken as a unit; thus, for example, a speed value of 533x corresponds to 150 * 533=79,950 KB / s, that is, about 80 MB / s.
In general, this parameter is quite specific; in fact, it is easier to focus on the directly claimed reading speed (see below). However, sometimes it is not indicated — in such cases, the speed value will be primarily 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.
Manufacturer's warranty
Manufacturer's warranty provided for this model.
In fact, this is the minimum service life promised by the manufacturer, subject to the rules of operation. Most often, the actual service life of the device is much 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 come across
a lifetime warranty, but in this case it is better to clarify the details of what it applies to. And in any case, it implies a certain period of time, though 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 (of course, not mechanical). But the difficulties in implementing this procedure (the representative office is located only in large cities) and the rare cases of the 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 chip.
