Benchmark Results: Read/Write Throughput
On most card readers, read and write performance is typically limited by the reader device. Therefore, we recommend looking for a device that specifically supports more than 20 MB/s bandwidth. SanDisk’s ImageMate proves a great solution, as it doesn't bottleneck the SD cards’ performance to less than 20 MB/s, unlike in our last SD memory card review.
The fastest card in this review (and the only product that clearly passes the 20 MB/s mark) is SanDisk’s Extreme. It sustains more than 25 MB/s on reads. Three other products are virtually identical when it comes to read performance: Transcend’s Ultimate 16GB, the Lexar Professional 8GB 133x, and Silicon Power’s Class 10 card. The smaller Transcend card has a much lower minimum throughput, making it a secondary choice for enthusiasts.
A similar picture develops when looking at write throughput results. SanDisk takes the lead while Lexar, Silicon Power, and Transcend follow in second place. Samsung cannot keep pace, but since its specification only says Class 6, we can't really object.
Our interface test reveals the maximum transfer speed of the SDHC cards in this review.
I see I'm not the only one who tried booting an OS off the SD card in my camera :-).
If I have write access times in the 100s of ms, doesn't that seriously impact how fast I can take photos? Some cameras can take 5 fps, so if I'm waiting 700ms for each photo to start writing, isn't that really bad?
@jsowoc: Not really, because the "burst" capture sequence uses the camera's cache memory, that will later dump it to the SD card. When the cache fills (usually very quickly) the camera's "burst" rate will decrease considerably, until you allow it to clear it's cache.
@TH: I don't doubt the quality and speed of SanDisk's products, but is there any posibility that the SanDisk branded card reader is "optimised" for SanDisk memory cards, and give better results for SanDisk-SanDisk combinations then any other combination?
I have an independent film (video) company, and our camera uses two SD cards (it seamlessly records to the second when the first is full). The only card I have been able to find that can "keep up" and capture the footage in hi-def is the Sandisk III Extreme (30 Mb/s rated).
I see I'm not the only one who tried booting an OS off the SD card in my camera :-).If I have write access times in the 100s of ms, doesn't that seriously impact how fast I can take photos? Some cameras can take 5 fps, so if I'm waiting 700ms for each photo to start writing, isn't that really bad?
Most Cameras that have a burst rate also have a built in cache memory for that so it can take pictures then it transfers to the card(may even be able to take more while sending the other pictures to the card). It helps to offset it a bit. Not saying you do not want the fastest card you can get your hands on. you still do.
The Patriod Lx series is missing.... They have 8gb -32gb sd cards...
The Patriod Lx series is missing.... They have 8gb -32gb sd cards...
*Patriot LX*
@TH I'm disappointed 2 things..
1 - No coverage of ATP or A-DATA which seem to be fairly fast (I find both faster than Sandisk Class 6 at least).
2 - No testing/benchmarks on Wear leveling, error rates, and recoverability. Many Pro Photographers swear by Sandisk & ATP because of their reliability, and recoverability with the unthinkable happens. Personal experience has taught me to avoid Lexar and Kingston
@sihastru, Even if the Sandisk Readers are optimized for Sandisk, I've fond them the most Reliable and consistent readers. They support ALL makes of cards, and even better than the Manufacturer's Own readers in many cases.
Did you guys forget to check power usage?
Interesting article. Will SDHC ever catch up to CompactFlash?
i bought my 8 gb SD card for $50 for my camera, damm its expensive...interesting article mate..
I'm really waiting for a cell phone with Andriod, Maemo or Meego that has a full-fledged SDXC slot. It's amazing that cell phones and portable media players have existed for over 10 years and we still don't have more than 32G memory in them.
Got my two SanDisk Etreme-III 16GB card for $69 CAD each, and that was before Xmas. Now I use one in my T91MT Tablet for add-on storage, more than zippy enough for everything not system based no lag for movies or anything.
For most cameras something class 6 or even slow Class10 is fine specially with a good local buffer, but for file transfer to the computer afterwards or for use in other situations like direct PC storage, I find the ExIII (30MB/s model) cards to be the only choice. ATP are fine (preferred their MMCplus cards since they were one of the few that sold them) but aren't as fast from my experience but close, and A-Data are more like the UltraII speeds (so likely closer to the Lexar Pro in this test).
Can't wait for SDXC to become more ubiquitous.
Interesting article. Will SDHC ever catch up to CompactFlash?
No, can't within spec (40MB/s on standard CF and 60+ on UDMA) but SDXC will catch and surpass CF.
The fact that only certain card readers can handle speeds above 20 MB/sec as stated in the article makes me wonder about the controllers in most cameras. For your typical entry level DSLR (or even a high end one that uses SD), are the controllers fast enough to read or write from/to something like the Sandisk card that can hit consistently manage speeds above 20 MB/sec in both directions?
Great article, just what I was looking for...
*goes off to buy Sandisk card*
That Sandisk and Lexar might be fast enough for a OS disk, but wouldn't CF be a better solution for someone in the market? CF can plug near-directly into an IDE port if necessary, and there are plenty of USB readers if that's the way you want to go.
Besides some high-end camera where $400 for an SD card pales in comparison to the $thousands you spent on the device itself, how are these cards practical? And do they even make cameras like that that don't use CF or internal HDDs?
I guess I'm surprised this article wasn't on Tom's Guide instead of Tom's Hardware.
No, can't within spec (40MB/s on standard CF and 60+ on UDMA) but SDXC will catch and surpass CF.
Unfortunately SD will never surpass the CompactFlash. CF will always have the upper hand since it is based on the PATA specification and therefore offers a high level of expandability. It is actually a derivative of the PCMCIA interface. The latest CF5.0 specification has a storage limit of 128 PetaByte compared to the SDXC that can only take up to 2 TB due to addressing limitations.
Also fathom that SD cards are smaller than CF cards and can therefore not fit as much hardware as a CF card, so therefore no matter how much capacity an SD card will have, a CF card will always be bigger.
Sure, one day SD may surpass today's CF cards in terms of speed but when that day comes newer generations of CompactFlash will implement a SATA based interface which is faster than PATA. There is already a variant available known as CFast which is built upon the SATAII spec. PCMCIA has evolved into the ExpressCard which makes it likely that a similar implementation will reach future generations of CF.