Minimum/maximum SD card size for a Pi 2?

I’m planning to put any library content on an external USB thumb drive so that it doesn’t get lost if I re-image OSMC on my Pi 2 so is there any benefit whatsoever in going above a certain size for the micro SD card for the OSMC imaged boot card?

I’m planning to get a Samsung Evo card (http://www.amazon.co.uk/Samsung-Memory-MicroSDHC-UHS-I-Adapter/dp/B00J2BU7WO) because I’ve heard that it has really good random read and write speeds which apparently is important for OSMC and other Linux/Kodi systems and I’m wondering whether there is any benefit whatsoever in going above 16GB. The only two possible benefits that I can think of are…

1 - Maybe more space to wear-level across to increase life and reliability but do SD cards even try to do wear levelling anyway?

2 - SSDs tend to have better performance as capacity increases, presumably due to parallelism of NAND chips in bigger devices. Does the same factor come into play in microSD cards or are they all single-wafer devices of differing capacity with no parallelism of access?

If neither of the above apply then I’m struggling to see any reason to go bigger than the smallest one available (16GB). I certainly have no space issues with my current 8GB Sandisk card running OSMC but am a bit unhappy with performance on a few things hence considering getting a new SD card.

  • Julian

A 16GB card will be fine.

Sam

Thanks.

I realised what an idiot I’ve been. I started a year or so ago with a Pi B and carefully researched the best SD card to buy. I upgraded to a Pi 2 a few months ago, a much much faster system, but it doesn’t take full sized SD cards of course. I had quite a few microSD cards already lying around though so I just used one of those; problem solved - except that I never gave any thought to the performance of the microSD card I was using.

I’ve now done some research and it appears that, to choose the worst case example, the 4K random write performance of the card I am currently using is about 1/200th of the performance of a Samsung Evo’s 4K random write speeds. Oops! Other random read/write differences aren’t as dramatic but still significant.

Time to splash out £6.29 I think (buying direct from Amazon not a reseller and not selecting frustration-free packaging to try to ensure a genuine product).

  • Julian

Samsung cards are pretty good, but you shouldn’t see that much of a difference compared to some other good cards.

Amazon are generally good (don’t buy from a private seller). We have cards at https://osmc.tv/shop too which are pre-loaded. They are not as cheap, but they are guaranteed to run on OSMC and you get the lifetime warranty.

Sam

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200/1 sounds excessive however I have seen a 20/1 difference in random 4KB write performance between cards.

A Kinston card I have will only manage 0.1MB/sec while my fastest Samsung card is about 2MB/sec for random 4KB write. This makes a massive difference to Kodi performance especially library scanning, but even just in general navigation around the menus.