Buying SD memory cards - important criteria

Whether for cameras, tablets or for notebooks - you can use SD memory cards almost anywhere. We give you some criteria that you should pay attention to when buying.

Find SD cards in the correct format

Before you can jump into the details of the SD cards, you first have to find the right format. This can vary depending on the device:

• Smartphones usually only support microSD cards. These are smaller than the classic memory cards.
• You can also use MicroSD cards with an adapter on a computer or in a camera.

SD card size for each device

An important criterion is of course the storage capacity. You are spoiled for choice here:

• Current memory cards range from 2 to 512 GB. Hobby photographers should use a memory size of at least 32 GB. If you also want to save music or films, you should choose an even larger variant.
• Here are some shortcuts: The original SD card (Secure Digital) only has a capacity of up to 2 GB. SDHC cards (high capacity) already allow storage capacities of up to 32 GB. SDXC cards (Extended Capacity) even move in the order of up to 2 TB. In practice, the largest SD cards are limited to 512 GB.
• With the storage capacity, of course, the price also increases: An SD card with 4 GB is available, for example, from just 5 euros. In contrast, the larger models with 128 GB already cost at least 60 euros. You can find the current prices in our leaderboard.

Buy SD cards with high write speeds

As soon as you copy the first files to your SD card, the next important criterion becomes apparent: the write speed. You have to differentiate between the minimum write rate and the theoretical performance:

• The minimum write speed results from the classes of the SD cards. The number of classes denotes the write speed in MByte / s. A class 6 memory card therefore offers a minimum write rate of 6 MByte / s. However, this is no longer appropriate. If you buy a new SD card, you should take at least one class 10 card.
• However, the actual write rates for Class 10 memory cards are significantly higher than the minimum write speed. Current high-end cards offer on average write and read rates of over 90 MByte / s.
• You should also aim for this when buying. SD cards with less than 90 MByte / s are usually no longer worth their money, especially since you can get the latest Class 10 models for less than 20 euros.
• However, make sure that your device supports the high write speed. Older cameras, in particular, often cannot use the data rates of new SD cards. Then the surcharge is not worth it. For current smartphones and other devices that are not older than two or three years, a Class 10 card is the right choice.

If your new SD card is not recognized, there is no need to worry: In another practical tip, we will explain how to get the memory card working again.