[kypfer]

Weird thought I just had … if I'm using an old slow SD card which takes some noticeable time to write, does the camera actually use more battery than if I used a more modern faster card with relatively short write times?
Purely a theoretical scenario … I've got fast cards if I need them … just wondering

[ramseybuckeye]

Maybe someone knows for sure, but I really doubt it. Anytime I've ever got new and faster cards I never noticed anything but the faster read/write.

[Wheatfield]

Weird thought I just had … if I'm using an old slow SD card which takes some noticeable time to write, does the camera actually use more battery than if I used a more modern faster card with relatively short write times?
Purely a theoretical scenario … I've got fast cards if I need them … just wondering

Probably, though I doubt if it would be enough to make a difference to the life of the battery. About all that would be using more power would be the little orange light that flickers during file writing.

[ProfessorBuzz]

It's specified by the SD card manufacturer, and depends on how the card is being used (read/write, which interface mode is being used eg 4bits, and more).
Here's a typical spec sheet for an older generation Kingston SD card in the 8-32GB range:

https://www.kingston.com/datasheets/SDCIT-specsheet-8gb-32gb_en.pdf

[R.Miller]

I never looked at one of those. Very interesting. Thanks for providing. So it looks like an average of about 200 - 250mA power consumption. You could then pull a spec sheet for each card and see what the power consumption is on those and extrapolate that over time for read/write maybe. I image it's not going to be a significant difference to even worry about.

[MossyRocks]

I would likely think that an older slower card would take more power than a newer one. This is because of process improvements, feature size improvements, design improvements, etc. In the end I would be surprised if cumulative difference over a battery charge was as high as one shot given that flash memory is pretty low power to start with.

[Not a Number]

I don't know how applicable this is, microSD cards were used in the testing and SPI mode was tested against UHS-I.

About halfway down are the power consumption test.
Experiment: microSD Card Power Consumption & SPI Performance | Gough's Tech Zone

"Current consumption overall was broadly similar on average in SPI mode – in the 20 to 25mA ballpark, with writes usually consuming higher currents. Attempting the same in UHS-I mode shows higher current consumption as the card is doing more “work” – sometimes higher draws in read purely because of the amount of bus and controller activity that occurs when reading at a speed that is significantly faster than the write speed. The peak current recorded was 300mA, while 100ms average current peaked at 80mA, significantly less than the numbers I had seen prior."

So the way I'm reading this and the datasheet referenced in the paper UHS-I consumes 2-4 times or more power as SPI mode. I'm assuming, perhaps wrongly, that older non-UHS-I cards us SPI mode.

[Fogel70]

UHS-I consumes more power per second, but it draw the power during a shorter period. So in the end it will most likely not make a major difference compared to using slower SPI transfer that consumes less power per second but takes longer time.

But it may also depend on the chipset used in the camera, as it may be better optimized for one type of transfer.
The power consumption in the camera itself is most likely a lot more than the power used for transfer images to the card. So I doubt it will make much difference in which type of card is used.

[Not a Number]

80 mA at 0.5 milliseconds is still more consumed than 20 mA at 2 milliseconds (hypothetical figures). It's still 80 vs 20 mA consumed. If you did four writes at 80mA at 0.5 milliseconds (2 milliseconds total) you would consume 320mA.

UHS-I cards get a lot warmer when used which points to much higher power consumption.

[Fogel70]

In the test the transfer rate was up to 500kB/s for the SPI mode. The read transfer rate during UHS-I was up to 80 MB/s and write transfer rate was up to 10 MB/s. (For the verbatim card)

Looking data from the test it seems that UHS-I is more efficient and use less energy per kB transferred data than SPI.

With transfer rate of 500 kB/s and 20 mA average consumption per 100 ms, SPI mode seems to consume 20 mA per 50 kb data, while UHS-I seems to consume 80 mA average consumption per 100ms, with transfer rate on 10 MB/s in sequential write mode, so 80 mA per 1 MB. But I do not know if the data in the test can be compared like this as there was a lot of different equipment used, and it was most likely not intended to be compared like this.

And I doubt this test data can be translated to what happen in a Pentax DSLR using different card types.

[kypfer]

Thanks to all who answered
Seems like my thoughts were of little consequence … nothing new there

[AstroDave]

80 mA at 0.5 milliseconds is still more consumed than 20 mA at 2 milliseconds (hypothetical figures). It's still 80 vs 20 mA consumed. If you did four writes at 80mA at 0.5 milliseconds (2 milliseconds total) you would consume 320mA.

Nope! It is current times time that matters (i.e. your battery is rated in mAh - milliampere-hours: how many milliamps can it supply, for how long)

80 ma at 0.5 milliseconds is 40 milliamp-milliseconds, as is 20 mA for 2 milliseconds- also equals 40 milliamp-milliseconds!

It's not just current draw, but for how long!

[mlag]

Just avoid the wifi enabled sd cards if you want saving energy...