Talk:SD card

X Speed Ratings: SLC vs MLC,?

Probably, a thing related to speed ratings of SD cards is the SLC vs MLC issue. Although it is almost never mentioned by SD cards distributors, it seems the critical factor impacting access times, write and read speed, as well as the media durability. I'm absolutely not any kind of expert here, I just wanted to give a hint, hoping it's usefull for soemone more knowledgable. I can't say what is the link between 60, 133, 150x etc. ratings and the SLC/MLC, but there is something on here it seems. Or are the MLC not present on the market anymore?

Searching for "slc mlc sd" gives eg. this document: The Samsung SLC NAND Flash Advantage.

Compatibility section

I think there should be a separate section on compatibility, e.g. between SD and MMC cards, the issue with 128 GB and larger SD cards, etc.

Disputed: 32 GB FAT32 limit

§ exFAT filesystem says that some SDXC host devices reject FAT32 file systems larger than 32 GB. That's been marked as needing a citation since September 2017 and although it's certainly possible (software may be arbitrarily perverse), it seems remarkably unlikely. Any objection to replacing it with a weaker statement that since such a file system violates the specification, it's not guaranteed to work? 209.209.238.189 (talk) 08:23, 21 December 2018 (UTC)

FAT32 on sdxc is not "endorsed" by the sd organization, but any sensible host should be able to read it. Wiekendraak (talk) 21:50, 28 December 2020 (UTC)

Powers of 1000 vs 1024

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

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Why are the capacities in the thumbnail descriptions given in powers of 1000 (or 10^x where x is an int), e.g MB, GB, TB, while elsewhere they are in powers of 1024 (or 2^x where x % 10 = 0), e.g MiB, GiB, TiB? I'm concerned because as the capacities increase, esp for TB vs TiB and PB vs PiB, the difference in bytes is huge.

Highlighted inconsitencies of powers of 1000 and 1024, in revision https://en.wikipedia.org/w/index.php?title=SD_card&oldid=957885871

Fezzy1347 (talk) 17:12, 25 May 2020 (UTC)

Good question. My (limited) understanding is that the maximum capacities are binary (see exFAT), but that the published capacities are decimal. Dondervogel 2 (talk) 19:27, 25 May 2020 (UTC)

As noted by Fezzy1347 the difference is important. Hence the revert. Dondervogel 2 (talk) 10:14, 3 May 2021 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

@Fezzy1347: @Locke Cole: This thread has been transferred to WT:MOSNUM. Dondervogel 2 (talk) 09:25, 7 May 2021 (UTC)

performance-loss with reformating

In SDUC > exFAT filesystem, it is mentioned twice that one can reformat the card. It is however not mentioned that one needs to know the exact specs (like allocation unit size and erase block size) of an SD-Card to do so, or lose up to 50% performance. Said specs are usually not profided by the vendors, even if asked, you have to guess them with flashbench.

Separate CSD Section

Card Specific Data deserves its own section in my opinion. All related matters like declared capacity may reside there. Siavoshkc (talk) 06:28, 10 February 2024 (UTC)

UHS-I DDR200 Controller

It is said in the article, that

"There is a proprietary UHS-I extension, called DDR200, originally created by SanDisk that increases transfer speed further to 170 MB/s. Unlike UHS-II, it does not use additional pins. It achieves this by using the 208 MHz frequency of the standard SDR104 mode, but using DDR transfers. This extension has since then been used by Lexar for their 1066x series (160 MB/s), Kingston Canvas Go Plus (170 MB/s) and the MyMemory PRO SD card (180 MB/s)."

There are also UHS-I microSD cards from Samsung (EVO Plus, Pro Plus, Pro Ultimate) which achieve speeds above 104 MB/s but are probably not compatible with the DDR200 specification. Such speeds are achievable only on Samsung readers (included with the card), and not on regular DDR200 readers (like Kingston MobileLitePlus). 83.242.66.85 (talk) 11:31, 13 March 2024 (UTC)