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CF vs. SD Cards: Which is faster? You’ll be surprised.

Our founder, Dana Neibert, just returned from a commercial shoot in which he ran into a problem that he normally doesn’t encounter. Usually, he shoots tethered which for the most part is instantaneous feedback as each image pops up on the screen as he shoots. But last week he shot a job where he was shooting to the CF memory card and shooting about 32GB every 15 minutes at which time each 32GB CF card had to be ingested into a computer so everyone could do a quick review. But waiting for 32GB of images to import while precious daylight was changing was not ideal.

He was using the fastest SanDisk Extreme Pro CF cards which can transfer data at up to 160MB per second. Using what is usually regarded as the fastest CF card reader, the Lexar Professional USB 3.0 Dual-Slot reader, each card was taking about 3.5 minutes to import into Capture One Pro. That doesn’t seem like a long time unless you have 25 crew and clients standing around anxiously waiting to see the latest images. So we did a test this week as he will be shooting for the same client again in two weeks and wants to cut that time in half if possible.

Doing a little research, we found that 160MB/s cards are the fastest CF cards out there. It doesn’t really matter what brand as they all more or less use the same chips inside and they have to base their speed rating on practical tests or risk losing all credibility. We’ve always used SanDisk Extreme Pro CF cards but as far as we know the Lexar Professional CF cards perform just as well.

Also, history has always dictated that CF cards outperform SD cards. But we decided to try a little SD card called the Lexar Professional 2000x SDHC/SDXC UHS-II. The speed rating on this card is 300MB/s which is nearly twice as fast as the fastest CF cards. But can an SD card really perform that well? Here’s what we found.

We filled two 32GB cards with raw camera images. The two cards were the SanDisk Extreme Pro CF and the Lexar Professional 2000x SDHC/SDXC UHS-II. The cards are rated at 160MB/s and 300MB/s, respectively. Below is a chart detailing the transfer speeds from each card to the latest MacBook Pro Retina with an SSD rated about 900MB/s which is more than adequate for both of those cards.

SanDisk Extreme Pro CF - 32GB
Lexar® Professional USB 3.0 Dual-Slot Reader
Transfer time: 3 minutes 19 seconds
MacBook Pro Internal SD Reader
N/A
Lexar SD UHS-II Reader
N/A
Lexar Professional 2000x SDHC/SDXC UHS-II - 32GB
Lexar® Professional USB 3.0 Dual-Slot Reader
Transfer time: 5 minutes 32 seconds
MacBook Pro Internal SD Reader
Transfer time: 5 minutes 42 seconds
Lexar SD UHS-II Reader
Transfer time: 1 minutes 49 seconds

You can see that CF card beats the SDHC/SDXC card using the trusty Lexar Professional USB 3.0 Dual-Slot reader. The internal MacBook Pro SD reader nets about the same import speed for the SDHC/SDXC card. But the SDHC/SDXC card really blows away the CF card once the dedicated Lexar UHS-II USB 3.0 reader is used.

Next we checked the in-camera performance of the SDHC/SDXC card versus the CF card. We wanted to see if there were any compromises in using an SDHC/SDXC card instead of the trusty workhorse CF cards. We used a Nikon D810 which has become one of the new standards in commercial photography as it produces very large 36 megapixel images. Each card was formatted in camera and the camera shot at five frames per second until the buffer maxed out. Here’s what we found.

Shots until buffer filled
SanDisk Extreme Pro CF Card
27 shots
Lexar Professional 2000x SDHC™/SDXC™ UHS-II
24 shots
Time for buffer to clear
SanDisk Extreme Pro CF Card
8 seconds
Lexar Professional 2000x SDHC™/SDXC™ UHS-II
9 seconds

You can see the CF card barely/slightly outperforms the SDHC/SDXC in the camera. But with the price of SDHC/SDXC cards vs. CF cards and the import speed to the computer, the SDHC/SDXC card is clearly the way to go—especially when you start going to the higher capacity 64GB and 128GB cards those transfer times will double and triple. The Nikon D810 SD slot speed is only UHS-I but as cameras start to implement UHS-II slot speeds, you can expect the SD performance to greatly increase. By the same token, we’re pretty sure CF cards will be introducing faster speeds in the near future to keep the race even.

pins

You can see the UHS-II card on the left has additional pins that the standard SD, high speed and UHS-I SD cards do not have. Most likely these extra pins are providing the extra bandwidth to help the UHS-II cards achieve these high transfer speeds.

Like we stated above, we’re really not married to any brand of memory card. But you will want to probably stay with better known name brands like SanDisk and Lexar as they do produce a quality product that, especially with memory cards, you won’t want to take chances with. We chose the Lexar SDHC/SDXC card over the comparable SanDisk SDHC/SDXC as for some reason the prices are really far apart and the Lexar card comes with the ultra high speed reader. Here’s a bit of a roundup of all the cards and readers covered in this article.

Lexar Professional 2000x 32GB SDHC/SDXC UHS-II/U3 w/USB 3.0 Reader/Image Rescue 5 Software
$54.95 at Amazon and B&H

SanDisk Extreme PRO SDHC/SDXC UHS-II Memory Card
(This is the SanDisk equivalent of the Lexar SDHC/SDXC card we tested—we’re not sure why it is double the price.)
$58.88 at Amazon and $59.95 at B&H

SanDisk Extreme PRO 32GB CompactFlash Memory Card UDMA 7
$44.95 at Amazon and B&H

Lexar Professional USB 3.0 Dual-Slot reader
$34.95 at Amazon and B&H

 


Put your DigiCase or Pelican case on any stand or tripod The DigiCase is the Ultimate DIT/DigiTech Case
Put your DigiCase or Pelican case on any stand or tripod
The DigiCase is the Ultimate DIT/DigiTech Case
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