SHOOTOUT: SD and CF cards for
digital cameras

Originally posted Monday, July 19th, 2010, by rob-ART morgan, mad scientist
Addendum on MacBook Pro built-in SD slot posted July 21st.

We recently upgraded our camera equipment. At the same time, we were looking at upgrading our memory cards. With compact digital cameras and pro-sumer digital SLRs doing HD video recording, your existing memory card(s) may not be fast enough. It also helps to have a fast memory card if you are doing continuous shooting.

The Nikon S8000 manual states, "Memory cards with an SD Speed Class rating of 6 or faster are recommended for recording movies." The "6" rating means at least 6MB/s. I say you should go for class 10 (10MB/s or better) just to make sure. Some Secure Digital (SD) card makers are now rating their cards in terms of MB/s. The SanDisk Extreme SDHC card we tested had "30MB/s" on the label.

In the case of Compact Flash (CF), a rating such as 300X or 400X is often used. The formula to figure out the transfer speed in MB/s is R = K * 150. So a 300X = up to 45MB/s and 400X = up to 60MB/s. Some manufacturers are now rating their cards in MB/s. The SanDisk Extreme CF card we tested had "60MB/s" on the label.

Regardless of the rating, the actual speed can be slower (or faster) than the rating.

I used QuickBench's "Large" test (2MB - 10MB test sizes) and various card readers to test the actual read/write speed of various SD and CF cards that are touted as fast performers to see if they meet or exceed the ratings and to see if they can be used for HD video on various digital cameras.

The first graph gives you an idea of how fast you can transfer photos or video from the memory card to your MacBook Pro.

The second graph gives you an idea of how fast your camera can store photos or video to your memory card.

LEGEND of GRAPHS (RED bar means FASTEST)
SanDisk CF 8G = Sandisk 8GB Extreme UDMA 400x CF memory card (SDCFX-008G)
Lexar Pro CF 8G = Lexar Professional Series 8 GB 300x UDMA CF memory card (CF8GB-300-381)

SanDisk SD 16G = SanDisk 16GB Extreme Class 10 SDHC Memory Card (SDSDX3-016G-P31)
SanDisk SD 8G = SanDisk 8GB Extreme Class 10 SDHC Memory Card (SDSDX3-008G-P31)
Transcend SD 16G = Transcend 16GB Class 6 SDHC Memory Card (TS16GSDHC6E)

ExpressCard reader = Sonnet Technology Pro Dual CF ExpressCard Reader (CFRW2X-E34)
FireWire 800 reader = SanDisk Extreme FireWire 800 CF Reader (SDDRX4-CF)
USB 2.0 reader = SanDisk ImageMate All-In-One USB Reader (SDDR-189)

INSIGHTS
We were reminded that the READ speed of the memory cards is higher than the WRITE speed.

The 16GB SanDisk Class 10 SDHC is much faster than the bargain 16GB Transcend Class 6 SDHC. In my opinion, you are better off paying $48 for an 8GB version of the faster SanDisk than $40 for the 16GB version of the slower Transcend. Having said that, if you believe the compact Nikon S8000's documentation, the Transcend may be adequate for both stills and video.

I was surprised that there were no FireWire 800 readers for SD cards. Even the ExpressCards for SD cards are really USB readers "in disguise." But after seeing how much faster the CF cards operate even on a USB reader, it's clear that creating a FireWire 800 or "true" ExpressCard reader for SD cards would be a wasted effort.

FireWire 800 readers do make sense for CF cards, but if you want your photos and video to transfer to you MacBook Pro in the fastest manner, the Pro Dual CF ExpressCard reader from Sonnet is one of the "true" ExpressCards. It can keep up with CF cards rated at 886X or 133MB/s. In our test, it enabled the SanDisk 400X CF to read photos much faster than with the FireWire 800 reader allowed. But if you are using an iMac or Mac Pro, the FireWire 800 reader is your best bet.

Lastly, we didn't test the really high end CF cards like the 600X (90MB/s) SanDisk Extreme Pro 16G priced at twice as much as the 400X (60MB/s) rated SanDisk Extreme 16G. They could be considered "overkill" since even the high-end Nikon D3X can't use the extra speed for storing photos, as Rob Galbraith found out in his extensive testing of flash cards and flash card readers.

ADDENDUM
The built-in SD slot on the 15" MacBook Pro Core i7 was also tested. It produced the same read/write speeds for the SanDisk SDSC card as the USB reader. Ditto for the iMac Core i7.

The only exception to our findings, according to Rob Galbraith, is the SanDisk ImageMate Multi-Card USB 2.0 reader that he reported as optimized for the SanDisk Extreme III "30MB/s" rated SDHC card. He measured 26MB/s.

BTW, some testing on the iPad using the camera kit produced a photo transfer speed of 8MB/s.

Feel free to email your thoughts to me, .

WHERE TO BUY SD and CF memory cards for digital cameras
You can buy the SanDisk Extreme Class 10 SDHC Memory Card direct from SanDisk or from Amazon
You can buy the Sandisk 8GB Extreme UDMA 400x CF memory card direct from SanDisk or from Amazon
You can buy the Lexar Professional Series 8 GB 300x UDMA CF memory card direct from Lexar or from Amazon

WHERE TO BUY SD and CF CARD READERS
You can purchase the Pro Dual CF ExpresCard/34 Reader direct from Sonnet or from OWC.
You can buy the Extreme FireWire 800 CF Reader direct from SanDisk or from Amazon
You can buy the SanDisk ImageMate All-In-One USB Reader direct from SanDisk or from Amazon

WHERE TO BUY A MACBOOK PRO and other Apple Products
Click on our Apple Store USA text links or display ads when you order a MacBook Pro. It's a great way to support Bare Feats since we earn a commission on each click-through that results in a sale.

 

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copyright 2010 Rob Art Morgan
"BARE facts on Macintosh speed FEATS"
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