Making sense of memory cards by Kim Komando ~ High Tech House Calls

Sunday, July 27, 2014

Making sense of memory cards by Kim Komando

5:07 PM High Tech House Calls, Expert Computer Consulting

Q. I'm taking a trip and need to grab a few more memory cards for my camera. I plan to take a lot of photos and some video. I was going to buy duplicates of the card I have, but my friend said I need something faster. How do I know what memory card is fast enough?
A. Taking several memory cards on a trip is a good idea. If one gets lost or breaks, you still have more.

I usually recommend buying several smaller cards rather than one big one just for this reason. Of course, no matter the size, you want to get a card with the right speed.

A card that's too slow will leave you waiting for files to transfer. Your camera might take seconds to take the next shot. You could miss a golden photo op while waiting for it to catch up.

You might decide to buy the fastest card, but you could be overspending. Plus, it might not even work with your gear. Fortunately, I can tell you what to look for.

First, you need to know what kind of card you're using. The most common type is the Secure Digital card.

When buying an SD card, you'll have a few choices to make before you even consider the speed.

There are three physical sizes of SD card: SD, miniSD and microSD. It's usually printed on the card so it's easy to tell what size you have. If you don't have a card already, check your gadget's manual to see what size card it takes.

Most cards will just list how much data they can hold. However, you might see other abbreviations dealing with storage amount.

Secure Digital Standard Capacity, or SDSC, cards can ranges from 1 megabyte to 4 gigabytes. Secure Digital High Capacity cards, or SDHC, range from 4GB to 32GB. Finally, Secure Digital eXtended Capacity, or SDXC, range from 32GB to 2 terabytes. Don't stress; you can ignore the abbreviation and just buy the amount you need.

Now that you know about choosing physical size and digital size, let's talk about speed.

There are five SD speed classes: 2, 4, 6, 10 and UHS. These represent minimum write speed; read speeds will be faster. For HD video recording, you want a class 6 or 10.

Check your gadget's manual for a recommended class. Some equipment will be optimized for a specific speed. There's no use spending extra on a class 10 card if your equipment won't support it.

UHS is faster than the other classes. However, these cards require compatible gear. You can't just put a UHS card in a regular SD slot and expect it to work. Again, check your gadget's manual to see what it supports.

SD isn't the only memory card type on the market. There's also CompactFlash, although it's becoming less common.

CompactFlash uses a different rating system entirely. And, predictably, it's even more confusing. It is based on a 150 kilobyte-per-second transfer rate.

For example, you might see a CF card labeled 45x. That means it transfer 45 times 150KBps. In other words, it transfers 6.75 megabytes of information a second.

You will also see 50x, 133x, 266x, 300x and 600x cards. For high-definition video, you'll want at least 266x. That's a 40 MB/sec transfer rate.

There is a problem, though. Manufacturers differ on what "transfer rate" means. Some use it to mean read speed; others to mean write speed. Some use it to mean both; others just make up a number.

Write speed is generally going to be less than read speed. A card with 266x read speed could have a much slower write speed. And it often won't say on the packaging.

Some manufacturers, like Kingston, specifically address read and write speeds. Other manufacturers are deliberately vague. You will want to do some research before buying a manufacturer's product.

There is one final thing to consider when buying any memory card. You may not actually have the memory card you think.

Counterfeit memory cards are very easy to find. These are typically offered for fantastic deals online, and they will look completely genuine. However, they will be slow and probably die quickly.

Click here to learn how to recover photos from a bad memory card.

You should buy cards only from legitimate retailers. Buying from a brick-and-mortar store is even better. You might still run across counterfeit cards, but you can return the card if it fails.

photos and some video. I was going to buy duplicates of the card I have, but my friend said I need something faster. How do I know what memory card is fast enough?

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