More and more digital products become part of our life, and we can see all kinds of memory cards more often than ever.
With such a large number of specifications and a variety of memory cards, getting the right choice for your needs is difficult, indeed.
Today, let's focus on how to choose the memory card, and I hope that this article will be helpful to you guys.
Introduction to Common Memory Cards:
After so many years' development of the memory card market, now the memory cards that we often see mainly include the SD card (Secure Digital Memory Card) and MicroSD card (known as TF, Trans-flash Card).
The former measures 24 x 32 x 2.1mm, while the latter is 15 x 11 x 1mm.
Due to the noticeable difference in the size, an SD card is often referred to as a big card, while a TF card is a small card. Small cards can be turned into large cards by using a special adapter.
In addition to SD cards and TF cards, you can also see CF cards, QDA cards, etc. on the market. As their application is limited, I won't go into the details of them.
Basics about Memory Cards:
Memory cards can be divided into different categories according to the capacity and speed class.
1) According to the capacity:
SD: the earliest version, SD cards are rarely found now. Up to 2GB;
SDHC: most widely used now, ranging from 4GB to 32GB;
SDXC: The most promising version, varying from 64GB to 2TB.
2) According to the speed class:
The Class is the early standard for the speed of memory cards.
The higher the Class level, the faster the transmission speed. Now, the common memory cards are Class 10, referred to as C10. Those with a lower speed, such as C6, C4, C2 cards have already stepped down from the stage.
UHS Speed Class:
The UHS (Ultra High Speed) is a brand new standard. Currently, there are three grades: UHS-I, UHS-II, and UHS-III.
UHS memory cards require UHS host devices to achieve the highest transmission speed. The high grade is compatible with the lower grade. If a device doesn't support the corresponding standard, a UHS-I/UHS-II/UHS-III memory card can be used as an ordinary one.
Generally, UHS-I (or 'U1') cards support at least 10MB/s write speed, UHS-3 (or 'U3') cards are for minimum write speed of 30MB/s.
The maximum read speeds of the UHS- I, UHS-II, UHS-III card are 104MB/s, 312MB/s and 624MB/s respectively.
VSC Speed Class:
VSC standards for the video speed class.
With the increasing demands of 4K videos, the SD Association set a video speed standard for video shooting. The graphical symbols use 'V' followed by a number designating write speed.
For example, memory cards for recording 4K videos must reach V30, and the smoother 4K videos must reach V60.
PS: Generally, the read speed, the speed class marked on the package of memory cards are the minimum level. We should know that in most cases, the read speed is lower than the write speed.
After you learn the above, you can easily understand the parameters on the memory card. Take this memory card as an example:
Brand and Series: SANDISK Extreme PRO Series
Read speed: 170MB/s
Class: SDXC memory card
Video speed class: V30 (minimum write speed: 30MB/s)
UHS mode: UHS-I supported
Class level: C10, (minimum write speed: 10M/s)
UHS rating: U3, minimum write speed of 30MB/s in UHS mode
In short, the card shown above is a 256GB SD card with the lowest write speed of 10MB/s in normal mode.
In UHS mode, the minimum write speed is 30MB/s, and the highest read speed is 170MB/s.
Apart from the above, on many TF cards, there are A1 or A2. What does it mean?
The speed is likely to lower during the sequential reading and writing of large files. The newly applied rating mandates a minimum IOPS for reading and writing.
So far, there are only two grades, namely, A1 and A2. A1/A2 memory cards have a minimum write speed of 10MB/s, but their minimum random read/write speed differs.
A Guide To The Purchase Of Memory Cards:
I've just introduced the basic knowledge of memory cards. Now, let's focus on the aspects to which you should pay attention.
Expensive products certainly meet your demand, but most users often ask for the performance-to-price ratio. Thus, you need to take into account the capacity, brand, and performance when buying a memory card.
How to choose the right capacity?
We should choose the storage capacity according to our actual needs. As photo- and video-taking are the main concerns, we should take into account these two aspects.
A 128GB memory card allows you to shoot 4K videos for about 3 hours, which is more than adequate for daily use. If each HD still photo is about 30MB, a 128GB memory card can store 4267 photos.
With the cost of the processor and particles taken into account, among mainstream SD cards, 64GB/128GB ones offer the best value for money.
If you often take 4K videos, it is recommended that you buy a 128GB memory card.
If you use a memory card mainly for taking photos, you'd better choose a 64GB memory card.
How to choose the right performance?
The essential specifications of memory cards are the read and write speed.
Generally speaking, recording high-definition videos necessitates high-performance memory cards.
For 4K footage and burst mode, the read speed should be over 200MB/s, and the write speed should surpass 90MB/s.
Of course, if you are not on a budget or to meet much higher demands, it is suggested that you have memory cards whose read speed and write speed reach 250MB/s.
When it comes to special needs like security, the speed is not critical. The stability, resistance to harsh environments (heat, water, etc.) are critical. Thus, you should choose memory cards which have been specially optimized.
How to choose from different brands?
SD cards are mature products, with barely any distinction between them.
However, their prices vary due to the positioning resulting from the differences in brands and costs.
As large manufacturers guarantee high quality, choose SD cards from famous brands, and you can enjoy the peace of mind.
As far as I know, TOSHIBA and Samsung memory cards are reliable.
If you ask for the cost-performance ratio, it would be better to choose brands like Lexar, Kingston, Teclast, Alfawise, etc.
FAQs about Memory Cards:
Q: I want to have 256GB storage memory. Should I buy a 256GB memory card or two 128GB cards?
A: In general, it is recommended to choose two 128GB cards. For one thing, two 128GB memory cards cost less than a 256GB one.
Using one 256GB memory card means the loss of all data in case of damage. Two 128G cards can share the risk of data loss. After all, it's better than ending up having nothing.
Q: I mainly use memory cards for taking photos. Which solution is better, using a TF card in addition to an adapter, or an SD card alone?
A: Since the conversion rate of the adapter is quite high, it will barely lower the performance. You won't have any problem with the transmission speed when using adapters from trustworthy manufacturers.
Q: How to choose the memory card for a dash cam?
A: As dash cams don't require high speed, but stability and resistance. It is recommended to choose those which offer an extended warranty period and improvements to tackle with hot and wet environments.
Q: Why can't my UHS-1 memory card reach the nominal speed while transferring files?
A: UHS-1 memory cards need to work with corresponding devices such as the card reader which supports UHS-1 to achieve the nominal transmission speed. If the device doesn't support UHS-1, the transmission speed will be lowered.
Thus, when buying a card reader, please check the supported transmission standards. Those only marked with USB 3.0 are ordinary card readers. They are at a low cost, but they offer slow transmission speed.
Q: On some memory cards, it writes parameters like 633X. What does it mean?
A: It is about an old-fashioned speed class rating, which is rarely used now. 1X equals to 150KB/s, so 633X is equivalent to 633 x 150KB/s / 1000, about 95MB/s.
Q: How to tell differences between UHS-I and UHS-II memory cards?
Method 1: Directly check the marks on the front of the package, on which there is the indication of Class.
Q: Which one is more important, read speed or write speed?
A: Manufacturers will mark down the speed on the package: R stands for the read speed; W stands for the write speed.
If there is only one speed on it, the speed must be the read speed, which is faster than the write speed.
Taking sequential photos or high-quality videos means a higher requirement on the write speed.
So as using Switch pr other game consoles.
All in all, you can finalize a reasonable choice based on your needs.
Here's a summary for those who directly jump to the end of the article.
TIPS for Buying Memory Cards
1) Consider well-known brands such as Sandy, Toshiba, Samsung, etc., prior to the cost-effective ones, including Lexar, Kingston, Teclast, Alfawise;
2) If you always need both SD and microSD cards to take still photos, consider buying a microSD card and an adapter;
3) If you need to record 4K videos, at least, you should choose a V30 memory card or above. Go for a V60 or V90 one, if possible;
4) If your budget is sufficient, it is recommended that you choose a memory card with a read speed of 200MB/s and a write speed of 90MB/s because it can meet most needs, even 4K footage and burst mode;
5) For taking videos, a memory card with 128GB capacity or above will be a great choice; otherwise, a 64GB one will be satisfying for you;
6) You should also pay attention to the differences between the read speed and write speed.