A flash drive or memory card is a compact portable electronic device with a memory function. It is used to store and transmit digital data. Today, a USB flash drive is widely used in conjunction with electronic devices such as a phone, audio player, camera, laptop and the like.
The first commercial memory card formats appeared only in the early 90s and had the PCMCIA specification. Now those "pioneers" are used only mainly for industrial purposes and in connecting I / O devices.
Some mistakenly assume that to select a memory card, it is enough to study only 2 parameters: the volume and which format is supported. However, it is not. For a truly objective purchase choice, there are five important aspects to consider (and this is the minimum). These include:
- Compatibility factors. It can be a supporting format, memory size, high-speed interface.
- Speed ​​class.
- Specific task.
- The presence of fake products.
- Reliability and quality of the flash drive.
Speed ​​classification
If about the first item, including format, volume and interface, some are at least a little, but in the know, then with the second, everything is much more complicated. In fact, the speed of reading and writing memory cards is no less important than the same compatibility. This issue is difficult to understand, but this point is very important to know.
The list of specific features makes it possible to describe the speed of cards in four ways. Manufacturers use them all, which leads to confusion in the definition of a flash drive class by an ordinary consumer. Below we will consider the labeling.
Classes and their marking
What does a flash drive class mean ? This is the speed class or Speed ​​Class, to which the minimum speed of the process of writing to a USB flash drive is tied. It is calculated in MB / s (megabytes per second). There are four varieties for standard cards:
- Class 2 - at least 2 MB / s.
- Class 4 - at least 4 MB / s.
- Class 6 - at least 6 MB / s.
- Class 10. Speed ​​is a minimum of 10 MB / s.
On ordinary maps, the speed class is marked with a number inscribed inside the letter “C”.
UHS Drives
Cards that run on the UHS bus are marked with the speed on themselves inside the letter “U”. Thus, for example, some classes of microSD flash drives with the UHS standard are indicated. At the moment there are only two of them:
- Class 1 - minimum 10 MB / s.
- Class 3 - minimum 30 MB / s.
The video standard USB flash drive class is indicated by the number to the right of the letter “V”. It has several varieties:
- 6 - from 6 MB / s;
- 10 - from 10 MB / s;
- 30 - from 30 MB / s;
- 60 - from 60 MB / s;
- 90 - respectively from 90 MB / s.
Application Performance Class Standard
There is also the Application Performance Class standard for memory cards. The class of flash drives of this standard is indicated on the right side of the letter "A". There are two types:
- Class 1 - with a minimum steady speed of 10 MB / s, with a random minimum reading of 1,500 IOPS (the number of I / O operations per second) and a random minimum record of 500 IOPS.
- Class 2 - with a minimum steady speed of 10 MB / s, with a random minimum reading of 4,000 IOPS and a minimum write of 2,000 IOPS.
As noted earlier, to indicate the class of flash drives use the value of the record to a minimum. In theory, a class 2 memory card might be faster than class 4 flash drives. And for this reason, manufacturers prefer to additionally indicate this point. You should always pay attention to this marking when buying a storage device.
Top speed
To emphasize the benefits of products, some of the manufacturers indicate in the description the highest speed possible to the maximum. However, you should not be guided by these figures. After all, usually here the speed is indicated not of writing, but of reading (which, naturally, is higher).
Also in this description, testimonies are obtained as a result of a synthetic test with ideal artificial conditions, which are unrealistic in everyday practice, where a whole bunch of external factors can affect the recording speed.
Multiplier Classification
With the advent of cards with a high speed of the recording process, you can increasingly see a pointer with a special multiplier on a flash drive. It is similar to the one used for marking the speed when writing and reading on an optical disc.
There are more than ten such factors in total. They start at 6x and end at 633x. One factor is 150 KB / s.
How to find out the class of the flash drive or its speed, if a multiplier is specified? To do this, simply multiply the indicated number by 150. The result will be the speed. For example, for a simple card with a factor of 6x, the speed will be 900 KB / s. Cards with the highest speed have a factor of 633x. That is, their speed is 95,000 KB / s.
Unfortunately, most memory card companies intentionally overestimate speed readings by assigning multipliers that correspond to reading rather than recording mode. Naturally, all this can lead the user astray, and he will come to the wrong conclusions. This point is also important to consider in the store.
Application area
Which class of flash drive is better? It all depends on what tasks she will have to cope with and in what area she will find her application. Here the principle of "bigger and faster" does not work, because in certain situations the volume and speed may become superfluous.
For example, if you need a card for a smartphone, then the main factor of choice is the volume, and not what class of the Micro-SD flash drive is. Indeed, in this case, we just need a good large memory drive. A high transfer rate for a smartphone is practically useless, since rarely anyone writes or reads a large file on the phone. Exceptions are smartphones with HD cameras and 4K video. In this case, both the volume and the class of the Micro flash drive are important.
What requirements should the storage device meet? In this case, this is at least class 6 or 10 for HD and U3 or V30 for 4K video. To record 8K video files with a frequency of 60/120 frames in one second, you already need the V60 or even V90 class. The larger the value, the better for the user.
Otherwise, the following devices should be noted:
- Speed ​​Class 2. This is the cheapest and, accordingly, the slowest speed class. It is the best solution for gadgets such as MP3-player, printer. For them, speed plays absolutely no role. But this class is completely unsuitable for actively used devices, such as a camera, camcorder, camcorder, etc.
- Speed ​​Class 4. It is suitable for amateur cameras that do not need high recording speed, but more importantly a matrix with good resolution. However, it should be borne in mind that the slowness in the recording of a flash drive can interfere with making an emergency shot at the right moment.
- Speed ​​Class 6. It is ideal in price and speed for digital cameras of the very first level. Great for shooting in JPEG format. The RAW format also supports, but can slow down, as the reviews say.
- Speed ​​Class 10. Used by professionals with expensive specialized photo and video equipment. Enables faster burst shooting. Within a second, several frames of maximum quality are recorded. This is a significant advantage for sports photographers. Class 10 cards have a large memory capacity and reach 32 gigabytes.
- For RAW shooting, it is recommended that you purchase a UHS class 1 and 3 drive.
As for storing photos, even professional photographers prefer cards with a small amount of memory to reduce the risk of losing images in unforeseen situations.
Please note that you should not store especially important information on only one medium. It will be prudent to make a backup copy of valuable data for more reliable safety and peace of mind.
Fakes
It has long been known that at least a third of the memory cards sold on the market are fakes of the original. To avoid disappointment with the purchase of a fake flash drive, do not buy it from dubious sellers and points of sale that are not credible. Also, do not chase the cheapness and unprecedented discounts. After all, the original card by no means can cost five times cheaper than the officially established price.
If earlier it was enough just to study the packaging well to make sure the purchase was authentic, today it can be falsified at such a high level that it is extremely difficult to distinguish it from the original. Therefore, special utilities have been developed to accurately determine the authenticity. So, for Windows it’s H2testw, for Mac and Linux it’s F3.
Reliability and quality
Many of us, at least once in our lives, were led to a cheap memory card without a name and lost important valuable data on it due to a breakdown. That is why, although the products of a well-known brand will cost you a pretty penny, such a flash drive will be reliable, and you will not have to worry about a possible breakdown and loss of very important information.
In addition to quality, a memory card with a well-known name will definitely have a high speed class and, importantly, a long guarantee. The speed of cheap popular flash drives with a capacity of 8 GB is often only 3 MB / s, which makes it difficult to work with them.
Conclusion
So, we found out what types of flash drives are. As you can see, today there is a huge variety of flash drives and memory cards. Therefore, in order to acquire a truly high-quality product that can last for many years, it is important to consider all the characteristics of the device. This article will help you choose the right flash drive specifically for your needs.