Do we really need Sandisk Extereme Pro 95mbps read & 90mbps write speed?

Started Dec 26, 2013 | Discussions thread
Michel J Veteran Member • Posts: 4,009
Re: Do we really need Sandisk Extereme Pro 95mbps read & 90mbps write speed?

May I had to the Allan Olesen comment that:

Sam_Oslo wrote:

Michel J wrote:

Alan_S wrote:

Ricky85 wrote:

thebustos wrote:

Some food for thought to throw into this:

Assuming this test is somewhat accurate, that's an almost 5 second difference with the extreme pro. That can be an eternity when you need to hit the shutter.

In this video I think it is the buffer performance...

Exactly (the OP's bottom line question was "Does Sandisk Extreme Pro really make a difference on Sony cameras?" - the answer illustrated in the video is a resounding YES, at least with the a77 and higher), and for anyone that uses burst shooting, the difference is dramatic. As the video demonstrates, you can save a few bucks on the slower cards and wait roughly 50% longer for the buffer to clear after it chokes on a burst. With the faster card, real life shooting with short pauses between shorter bursts is virtually unlimited as the buffer clears so much faster.

That SanDisk Extreme Pro SDHC UHS-I 45Mb/sec (8 Gb) is rated at 45 MB/s but it writes much slower in reality. It's benchmarked at ~38 Mb/s. The same site has tested SanDisk Extreme Pro SDHC UHS-I 95Mb/sec (32 Gb) and it's benchmarked at ~84 MB/s (which saturates camera's write-speed anyways). If these benchmarks are accurate, then that test are not accurate.

The performance of the buffer is nothing without a fast memory card to empty all the collected burst, imho.

The one bellow seems to have a witting speed as fast as the buffer is (Toshiba claimed 240 MB/s, to have the speed "to allow high-resolution photos to be snapped and saved continuously"):

I was lucky to get the Sony at an affordable price, because now I could keep this Exceria instead the SanDisk to take a try. That should confirm (or not) that the buffer performance need to go in par with the memory card performance to increase the flow of the burst. And not suddenly feel that the camera freezes at the same time as they write on the SD card.


There is a limitation for how fast the camera can write from buffer to the card. If I'm not mistaking that's around 50 MB/s for A77. The Camera needs a USB3.0 interface for transferring at 240 MB/s (from buffer to SD card), but that's not the case here.

I have no idea, if, why and how the outside USB port is the same chipset used for the in-camera data transfert. Anyway I should buy the Toshiba instead the SanDisk to be in compliance with the generation next already, and to get the best from the available in-camera data/rate transfert.

Moreover, it's seems to be one or more mistakes appeared from few posts now:

  • I'm not sure if 24MP does mean 24 MB/s really !?!?
  • Who knows if there are no other factors that slow down the dedicated data rate transfer, such as some in-camera upstream treatments, which although possibly made ​​in real time, will not speed up the process downstream, also true for the opening/closing session protocols of a burst flow, and so on.

Many things I don't know. Anyway, the today theoric data transfert rate, is actually not according to the SD-card performance 'till now imho, but if yes, we have to explain why(?) to understand better that point.


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Michel J
« Having the latest gear is nice, but great photographers don't have to have it. They can shoot good stuff with anything »

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