[lug] SD card reader and fast cards

[stimits at comcast.net]

> > > <gary.hodges at noaa.gov> wrote:> > >> Hi. I have a few very small form factor computers that use a SD card for> > >> the system drive. I'd like to buy faster cards for these computers,> > but I> > >> would first like to determine if the card reader in these machines will> > >> support the cards I want to buy. I have one of these currently running> > >> Ubuntu. Is there a command I can run or a system spec I can look for?> > >> > >Can you be more specific about what kind of devices?> > >> > >For the Raspberry Pi, I think there's a wiki page detailing people's> > > experience with different cards. Other systems might have something> > > similar, though the Pi is likely to be the best-documented with the> > > largest set of cards...
> >
> > nVidia Tegra 3 and Tegra K1 devices. These are ARMv7, similar to the> > newer second generation Raspberry Pi 2. I've had the same results> > whether working with SD cards on newer/faster K1 or older/slower Tegra 3.
> 
> FWIW I've only used a Lexar Professional, SDHC, class 10, 16GB, 133x in > these to date.
> 
> http://www.amazon.com/Lexar-Professional-Class-Flash-Memory/dp/B003JTHN2W/ref=sr_1_1?ie=UTF8&qid=1436292273&sr=8-1&> keywords=lexar+professional+sdhc+16GB+133x
> 
> The card I am considering is:
> 
> http://www.sandisk.com/products/memory-cards/sd/extremepro-sdxc-sdhc-uhs-ii/
> 
> http://www.amazon.com/Sandisk-Extreme-Digital-Capacity-SDSDXPB-016G-A46/dp/B00ITCHW4S/ref=sr_1_7?ie=UTF8&qid=1436224065&sr=8-7&keywords=sandisk+extreme+pro+sd
> 
 
I have no experience with those specific SD cards. SanDisk class 10 SDHC (suitable for 1080p) has consistently worked for me on all devices for all purposes, so if I were in the market for something to work with 4K video this is one I'd probably be willing to try. Whether or not your hardware supports the SD card format for this is another question since UHS has an actual wiring difference that the embedded system would need to support (the Ultra High Speed "UHS" bus). Wikipedia has some good information:
https://en.wikipedia.org/wiki/Secure_Digital
 
I would guess that most embedded/SoC devices which are even a little bit "old" won't support UHS. Tegra K1 is a beast of absolute video speed, but even this won't support 4K formats. The newer Tegra X1 would have no problem dealing with this, it was designed from the start to support 4K. I do not currently know of any other small embedded SoC which deals with 4K as well as Tegra X1. 4K video hardware of other SoC that handle 4K would be very rare and expensive in comparison. I guess a question about this is whether it is 4K video format you are interested in? If not, you may be better off using the fastest SDHC card you can get, and avoiding UHS.
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