Different classes of SD cards

[diablo81588]

Careful. I have used class 10... it doesn't work for our phone... I'm saying the common person won't notice the difference. That's all... I'm not disagreeing class 10 is better, I'm simply saying a class 4 will work fine for most.

Sent from my DROID RAZR HD using Xparent Cyan Tapatalk 2

Of course it will work fine. I never argued that class 4 was unreliable, only that they were slow in comparison. I think it's pathetic that brand new phones can't handle cards that have been available for years, especially when a phone that's well over a year old works fine with them.

Sent from my DROID BIONIC using Tapatalk 2

[jntdroid]

And there's simply something funky about those Sandisk Class 10's in these new Moto phones - that's why I said what I did initially. Class 6 might be a good balance. I've had 2 Maxx HD's and 3 M's, and tried 3 different Sandisk Class 10s - behaved the same all across the board. A few days would go by fine, then one day I'd reboot and half of my content was thrown into the Lost.Dir directory, which basically means gone unless you really want to dig deep.

[Spey]

Razr M OTA JB 4.1.1
32GB Class 10 performs well on my device
KingstonMicroSDHC 32GB Class 10 SDC10/32GB

Access times are noticeably faster than previous card (Patriot 8GB Class 4). Speed comparison based on both cards being around 50% - 60% capacity. Everyday type stuff is not where yu really notice ANY speed difference. But, for example; I just inserted one of these cards into my Razr M (first time this phone has seen this card), card from another phone with lots of music and photos from the other phone (like around 20GB of stuff). Took about 5-seconds for the device to be able to access all the photos folders and the music. With slower cards the initiation process to locate everything is much longer, and this specific card came from a Windows Mobile Phone running WM-6.5 dual booting from the card into Android Froyo from a folder stored on the SD-card.

I think there is a VALID case to be made for the faster speed Class cards:
1) Writing to the card Video & Photos (transfers and/or sequential shooting).
2) Music (first time you load a bunch of music and the device sees the music the 1st time = much faster).
3) Transfer To/From the Card (large files and/or folders of files).
4) Simultaneous HD Video & Still Capture (I don't do this, other may)

I suppose if you are only accessing small amounts of data at a time, speed class probably not to much an issue. But for those of us who do things related to the SD -card and it's like ho-hum ok hear it comes, the faster card is for sure more snappy response times (keep in mind this is comparing Class-4 @4Mb/s to Class-10 @10Mb/s). Example: music folder with lots of songs, photo folders, movies, etc. For most everyday tasks Class-4 probably everything most folks need, with one exception Full HD video recording and HD still consecutive recording. HD recording on Class-4 is acceptable by itself and my guess very few are doing "stills" simultaneously with HD Video ...?

Anyone with first hand experience with UHS-I Card running in Razr-M (working / not working, etc.)?
I am looking forward to trying out the newer UHS-I (50+Mb/s based on clock-frequency-support) to compare to the Class-10's in real world performance comparisons (things I do on regular basis). Other factors play into the scene with the Ultra High Speed cards though like clock-frequency support, etc. Users need to understand that the "theoretical" speed is most likely exponentially faster than they will ever achieve. Right now I think the Class-10 32GB is the "value" purchase.

Update: (few additional thoughts & considerations based on my experiences)
1) Forgot to mention user needs to also consider how they format the SD-card, with regard to the performance expectations and capacity related to how they plan to use the card (do ya just want to store lots of stuff, or do you want to have fast access ...?). This becomes even more important as we move on to larger cards 32GB/64GB/etc. How we "choose" to divide the card up, has an effect on how fast the card can perform and also how much actual data can be stored on the card.
2) Consider - just because a card says it's Class-X does not mean that's how it will perform. I have some Class-4 SD-cards that will not read or write at 4Mb/s (some as low as 2.1), and I have some Class-4 that perform at over 5Mb/s (same brand, same model # & not limited to "off brands"). You need to be able to do a few read/write tests, then average your values to determine specific performance of a given card.
3) When running or installing an O/S from a SD-card, many times a device will be extremely finicky with regard to both the specific card and the formatting (Example: loading & running Android O/O's on Nook Color Devices, loading an O/S to internal memory for the first time).

Regards,