Will I benefit from using a very fast SD card, such as this SanDisk Extreme Pro card, in my non-UHS enabled camera (a Pentax K-5)? I do not have any devices that can take advantage of UHS speeds. Will there be a performance advantage, even if small, from using such a card?

This is a more generalized version of this question: Can I get faster and cheaper results by buying the Sandisk Extreme, not the newer Pro?


2 Answers 2


A camera can only write out information so fast. So once you have a card that can be written to as fast as the camera can write out there is no benefit to getting a faster card. The I/O bottleneck is on the camera side. The only benefit you'll see is when it comes to reading off the card onto the computer. Whether that benefit is worth the cost difference is a personal decision.

Honestly, for me, I generally stick with slower cards. The camera buffer is large enough to handle short bursts and by the time I'm ready for another burst the card has had sufficient time to clear the buffer.

  • \$\begingroup\$ Good answer. Lets not forget the camera buffer in its self is flash memory - maybe find the write speed of that and compare \$\endgroup\$
    – Rob
    Commented Apr 9, 2012 at 9:29
  • 1
    \$\begingroup\$ No. The buffer is typically SDRAM similar to that of computer memory. \$\endgroup\$
    – bwDraco
    Commented Apr 9, 2012 at 14:22
  • \$\begingroup\$ Ah! sorry your right! - SDRAM is far quicker than flash \$\endgroup\$
    – Rob
    Commented Apr 9, 2012 at 20:00
  • \$\begingroup\$ By orders of magnitude. Undoubtedly they are using slower ram than what you'll find in a modern computer but it's still much faster than any nvram. Although it wouldn't surprise me if there is a small transitional buffer in nvram but I haven't looked into that before. \$\endgroup\$
    – nwcs
    Commented Apr 9, 2012 at 22:09

UHS and UDMA are two different but related standards, and support for UHS is not necessarily a requirement for "using" cards faster than 30mb/s. UHS cards are still UDMA compatible, and will revert to the UDMA interface if UHS is not supported.

As for whether using a speed faster than 30mb/s will help, probably not with an SD card. I think the maximum write speed in SD/SDHC cards is 30mb/s (Class 10), while the read speed can be faster than that on the same interface. You only gain the improved write speed benefit if your interface is UHS compatible.

As a side note, if you use Compact Flash (CF) cards, you can definitely get very fast speeds with UDMA interfaces. I believe UDMA-6 has reached 90mb/s or around there, and UDMA-7 has reached 150mb/s (with Lexar 1000x cards). The SD/SDHC standard has kind of stagnated, and it seems its been stuck at Class 10 (30mb/s) for quite a number of years. The UHS standard does not seem to have caught on as well as some expected as well, and the SDXC standard, which will supposedly support up to 300mb/s, has not materialized all that well either. Some SDXC cards exist at speeds over 100mb/s, and a few cameras (mostly compacts, I'm not aware of many DSLR's) have supported it since the beginning of 2011.


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