28Feb PRETEC SDXC 64GB V.S. Sandisk Extreme SDHC 32GB Speed test
The PRETEC SDXC 64GB class 16 card clocks in at $75, while the Sandisk Extreme SDHC 32GB 45MB/s card will set you back about $64. On one hand the Sandisk Extreme SDHC cards are well respected and considered to be well worth the money, while PRETEC made its name as one of the first companies to release a SDXC UHS-I (Ultra-High Speed) class memory card.
It’s clear that the PRETEC SDXC card is a better value when looking at price per GB. The extra $10 rewards you with 32GB of extra storage space which means you can fit almost a whole day worth of filming on a single card. But how does it stack up in the category of write speeds?
When I found these PRETEC SDXC cards, I went ahead and ordered a set of them, one for each of my Canon T2i cameras. As a measure of quality control I’ve run the same tests on both of these cards to see how they preform. For each of these tests I’m using the H2testw 1.4 flash drive testing program. This is a pretty handy testing tool that writes directly to flash memory in 1GB file chunks and records there average write speed over a length of time.
The first PRETEC SDXC card I tested preformed great at 18.2 MB/s. If you’re not sure how this stacks up against other cards, check out this earlier post. Basically the Canon t2i, t3i, and 60d require a constant write speed of about 6.25MB/s, a constant 18.2 MB/s gives you quit a bit of head room to work with.
The Second PRETEC SDXC card I tested wasn’t quit as impressive as the first. The speeds on this card averaged out at 17.5MB/s which is still a very good number, but it’s interesting to see that the same brand of card gives you 700KB of difference in speed.
I only have one 45MB/s Sandisk Extreme card in my collection to test, the other 32GB cards are 30MB/s. So I figured I would test both of these speeds and see how they preform against the PRETEC SDXC cards. The Sandisk Extreme 32GB 30MB/s card runs about $60, that’s about $4 less then it’s slightly more advanced brother, so lets see how it preforms.
The Sandisk Extreme 32GB 30MB/s card did pretty good at 15.3MB/s which is still more then enough speed to handle Canon’s video codec with room to spare for increased data rates with Magic Lantern. But even the slower PRETEC SDXC card out preformed this card by 2.2MB/s.
It’s no surprise that the Sandisk Extreme SDHC 32GB 45MB/s card out preformed it’s slightly less expensive brother by 1.6MB/s, but 16.9MB/s is still a slower write speed then either one of the PRETEC SDXC cards. It looks like the PRETEC SDXC 64GB class 16 cards are the best value in terms of speed and space. I am very pleased to see the speed results of the PRETEC SDXC cards so far and with the few Magic Lantern tests I’ve been able to run, I’ve managed to get a constant 1.5x CBR without dropouts.
These PRETEC SDXC cards aren’t the absolute fastest cards on the market, but they have more then enough head room to allow for higher bit rates and more recording space without much problem. They defiantly have a better performance to price ratio when compared with these mid range Sandisk Extreme cards. I plan to take these PRETEC SDXC cards out with me on the next few projects I work on and see how the hold up. I’ll be sure to write a post on their performance again once I’ve had a chance to use them for a few months and see how they hold up.
February 28th, 2012 at 9:16 pm
Running it at CBR 1.5x you are obviously using Magic Lantern. I have had problems after low-level formatting my recently arrived 64GB Pretec card and maintaining the boot flag, have you tried reformatting your cards yet, and did ML still boot? Did you also have to set the boot flag with the EOScard.exe utility? I’m running on the T2i also.
February 28th, 2012 at 9:36 pm
Thanks for the tip on the card tester. Something you should know; I ran the test on my USRobotics USB 3.0 reader, here are my results.
Writing speed: 32.5 MByte/s
Reading speed: 48.5 MByte/s
I’m thrilled, and super thanks for the tip a week ago about the Newegg price, you are the reason I picked mine up.
February 29th, 2012 at 6:18 am
The write test I used generates a little lower results because of the way the data is written to the card. H2testw 1.4 writes 1GB files to the card then averages out the overall speed until it fills up all space on the card. That method seems to more closely mimic the way Canon writes files to the card.
Tests with other programs (like HDtune) will give you better results because of the way data speeds are tested on the card. No matter what testing method you use, the PRETEC cards win.
February 29th, 2012 at 1:11 pm
I used the test you wrote of, H2testw 1.4 from a German site, did you use a USB 3.0 reader?
Also, have you been able to low-level format in camera the Pretec card and keep the boot flag active?
February 29th, 2012 at 1:52 pm
The card reader I ended up using was USB 3.0 though I don’t think it would matter much at these lower data rates. If I remember correctly, usb 2.0 is good up to 60MBytes/s (480Mbits/s). I haven’t tried to format the card from the camera. I used my desktop to format the card, and set the Boot Flag with EOS utility. Are you having trouble formatting the card in your camera? I’ve never actually tried that.
February 29th, 2012 at 3:47 pm
On smaller cards, formatting in camera is brilliant. Some time ago the Magic Lantern team figured out how to low-level format the card, holding all Magic Lantern files in memory and then rewriting them to the card, great time saver! If you are using a build older than December 2011, I’m not sure if this formatting feature was available in the previous general release.
Yes, I’m having a problem formatting in camera on the 64GB card, which has been acknowledged as a known issue, I was just wondering if you were having the same difficulty.
February 29th, 2012 at 4:32 pm
I’ll give it a try when I get a chance and see if Magic lantern supports that option. I normally create one settings file for all of my cards and then format and copy it to all of them on my laptop. Formatting and copying files to the 10 cards I use for filming takes a little less then 45 min. It’s something I’ve gotten used to doing while i’m packing gear.
The option would be nice in camera, but then I’d have to check the settings on each card every time I grab a new one.
March 29th, 2013 at 9:35 am
Hi,
I’m thinking about buying a Pretec card, and I’m curious of how the one you bought work? Regarding John Wise’s comments, did yours work fine with ML? How about formatting issues?
March 1st, 2012 at 7:53 am
Good idea for a future episode is to explain your card formatting process, just a thought.
March 1st, 2012 at 9:16 am
I’ll add Data management to the video list, good idea Joe.
March 30th, 2012 at 10:07 am
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