SDHC vs SDXC: What’s the Difference and Which is Best?

sdxc or sdhcIf you’re wondering what the difference is between SDHC and SDXC memory cards and which one is the best, you aren’t alone. Let’s take a look at what these newer cards have that the usual ones lack and explore the differences between the two cards.

To understand SDHC and SDXC memory cards, you first need to understand SD cards. SD stands for Secure Digital memory card and can be used to store files, pictures, videos, music, and any other data you want to store.

These cards are supported by most devices that store data on memory cards, such as cameras, tablets, smartphones, and PCs (which require compatible card readers). A regular SD card has limited storage capacity, while SDHC and SDXC cards have more storage and can support faster data transfer rates.


Main Difference Between SDHC vs SDXC

The main differences between SDHC and SDXC are:

  • SDXC cards offer up to 2TB of capacity, whereas SDHC cards tend to cap out around only 32GB
  • SDHC is compatible with both SDXC devices, whereas SDXC is not reverse compatible with SDHC devices

SDHC – A Primer

SDHC is one of the most-used removable memory cards in cameras and camcorders because of its high-capacity storage. Where the older SD cards have only up to 2GB of storage, SDHC cards have anywhere from 4GB to 32GB. This means you can store more photos and videos with no worries about running out of space. SDHC cards are also compatible with a wide range of cameras and camcorders. Check your device; if it says it’s compatible with SDHC, you can also use SD cards. But if it only says it’s compatible with SD cards, you probably cannot use SDHC cards.

When evaluating memory cards for camera use, users often overlook one component of the SDHC card, and that’s its speed capacity. The memory card’s speed is very important when filming on a high-resolution camera because it ensures that you are able to capture everything smoothly. A slower memory card is likely to become overwhelmed and could potentially not record at all.

SDXC – A Primer

SDXC cards have even higher capacity than SDHC cards. Compared to SDHC cards, SDXC cards start at a higher memory capacity (64GB) and theoretically can go up to 2 Terabytes. This potentially means much longer high-definition videos for camcorder users than SDHC cards can offer.

In addition to the higher memory capacity, SDXC cards also offer higher transfer rates. While the SDHC card’s speed capacity goes only up to 10MBps, the SDXC card has a maximum of 300 MBps. One thing to realize is that speed capacities for either card are categorized into four different classes.

These are Class 2, 4, 6, and 10. Class 2 offers up to 2 MBps, while the other classes offer up to 10 MBps. However, depending on the card’s manufacturer, you may not be able to find the speed class of your card. Still, do check for it when buying a memory card; if you can find it, it can help you make your decision.

Some standard definition cameras may do just fine with a Class 2 card, whether SD of SDHC. However, if your camera is high definition, you’ll want to try to choose a Class 4 or 6 card because they are faster and can better handle the transfer rate of high definition recording. SDXC cards are usually offered to camcorder users because of their faster speed compared to SDHC.

How Does SDHC Format Differ from SD?

So how does the SDHC card compare to the older SD card? The main difference between the two are the default file formats and the maximum storage capacities. While a standard SD card can store up to 2GB of data and uses FAT16 as its default file format, the SDHC card has a storage capacity of anywhere from 4GB to 32GB and its default file format is FAT32. You can get either type of card in three different sizes: micro SD, mini SD, and full SD. These refer to the physical size of the card.

As for compatibility, standard SD cards are backward compatible but not forward. What this means is that a device that is only SD card compatible will not support an SDHC card (and, obviously, not an SDXC card either), but devices that support SDHC cards can usually also read and write to SD cards. Likewise, an SDHC device will not be able to support an SDXC card, but an SDXC device can usually support an SDHC card as well as an SDXC card.

The other issue that matters is transfer speeds. When you use an SD card with a camcorder it needs to be able to save data as fast as the camcorder can stream it. Higher video resolutions mean more data is streamed per second. Just as with SDHC and SDXC cards, SD cards have speed class ratings of 2, 4, 6, and 10. SDHC and SDXC cards also have a speed class of 1, which is also called Ultra High-Speed Data Transfer. This is the fastest class and is not available with standard SD cards.

Which Memory Card Is Right for You?

There’s more to choosing a memory card than just buying the one with the most storage. You may not need an 8GB card! One of the things you should consider is the type of photography you are planning to use the card for.  For example, will you be doing sports photography where you need to take hundreds of photos rapidly? Or will you be doing another type of photography where you only need to take a few shots per session?

Also, how much time will pass between taking photos and downloading them to your computer? If you can’t or won’t download images regularly, you may want to choose a card with a larger capacity. You also may want more than one card to have on hand, because cards (Just like everything else) do malfunction. If you happen to be on location without an extra card, you could lose valuable shots or videos. For this reason, having a few 2GB or 3GB cards may be a better option than having one 8GB card.

Tips for Using Your SDXC or SDHC Memory Card

Regardless of the type of memory card you choose, there are some things you can do to get the most out of your card. First of all, should you have a disaster such as accidentally deleting images or seeing a card error message, stop using the card immediately. You may be able to recover your images. Continue to use the card, and you run the risk of overwriting your other images. There are data recovery tools that may be able to restore your data.

When deleting images, it’s best to do so on your computer, not on your camera. It may surprise you to learn that deleting images from the card while still inside your camera can actually shorten the card’s life. The fewer times you add or remove data, the better. When you erase all your images at one time on your computer you put the card through fewer erase cycles. Alternately, you can use the camera’s format function each time to wipe the card and start clean.

Periodically reformatting your card is a good idea. Every now and then reformat it to wipe images, file names, and any other data to start over clean. Of course, be sure you’ve downloaded any images you want to keep before you do this! When you format the card, do so with it in the camera you want to use it with. This helps ensure that the card is formatted specifically for your camera. While you’re at it, you should replace your card occasionally anyway; memory cards do not last forever and updated now and then will give you the best results. Fortunately prices have been coming down, so this isn’t as difficult as it used to be. You should also keep your camera up to date.

In using your card, switching your camera off before you remove the card is a good idea. Also don’t let your camera’s batteries die completely; keep an eye on their charge to prevent the camera from shutting down in the middle of writing an image to your card. And keep in mind that your camera may need time to write all the data when you shoot in burst mode, so don’t turn it off too quickly when you’re done shooting. This isn’t a problem with some newer cameras, which will continue buffering after they are turned off, but it’s a good idea to be safe rather than sorry.

Finally, take some common sense steps to care for your cards. Keep them clean and dry, and don’t expose them to temperature extremes. Do not drop them, bend them, puncture them, or expose them to h3 electro-magnetic currents. Store unused cards inside plastic bags for added protection. Following these tips can help you get the most out of your memory card, whether you decide that an SD, SDHC, or SDXC card is right for you.

Robert Alexander

A camera geek and freelance photographer, Robert (Aka "Rob" or "Bob") spends way too much time examining the finer points of cameras.

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