Real-world difference between MicroSD classes

[Mr. Pedantic]

So, I know about the difference between Class 2, 4, 6, and 10. But is there any difference between them in terms of loading apps, playing/recording video, system responsiveness, etc?

I know that for video recording and stuff, Class 6 or more is better because of the bitrate of the video, but the video I can record on my phone is nowhere near HD so that's not an issue and the only other thing I can think of that could use the bandwidth is loading apps.

So does having a higher-class card give you a faster phone, or is there a point beyond which the processor is the bottleneck for general usage?

I'm using a Galaxy S 16GB phone, if it matters.

 

[gaidensensei]

Yeah, had a discussion with a dev and learned that in the rom flashing world (for android) SD card r/w access is part of what they (devs) classify as 'improvements' and utilize to distinguish performance between roms rather than video performance benchmarks from quadrant and q3timedemo, etc.

You already know the differences between the classes, and it does involve video recording. Sometimes the 720/1080p recording abilities on some phones stutter because they're recording to the sdcard -- at pitiful speeds of theoretical 4/6mb per sec is what causes the 'shutter lag' for certain devices.

 

[Mr. Pedantic]

Well, quadrant tests IO as well, right? So that's not surprising. But Q3...?

 

[gaidensensei]

Kwaak3 (quake3) reads from the sdcard since you copy the baseq3 files into there, but since everything is precached before the map loads it kind of defeats the purpose of the benchmark other than comparing overall scores. The same is going on with quadrant too, no one really knows how the calculations are done but video performance apparently affects the score greatly.

In general, I think that having a faster sdcard has it's uses, but they're minor. Particularly when making large file transfers, nandroid backups, loading large pic gallery, etc that kind of stuff, but for general OS/UI performance I don't think it's going to be anything granting mind-blowing speeds.

 

[Mr. Pedantic]

I see. Is there any point where if you slow the SD card any more performance drops dramatically, or can you go all the way down to Class 2 and see only minor incremental performance differences compared to Class 10?

 

[BabaBooey]

From own usage of these in android smartphones...depending on brand I have had class 4 cards beat a class 6 so best bet is to stick to major brand names and I now have a class 10 in my evo4g and can tell the difference in performance from the class 2 it came with.

Video is a obvious choice,you need a class 10 for hd video.

So I say it is worth the extra for a class 10 card.

 

[poofyhairguy]

I can tell a HUGE difference between my Class 10 card and my Class 2/4/6 cards when I install apps to them. If I had an HTC phone where I had to load all the apps from SD I would only have Class 10.

Otherwise they are the same.

 

[Mr. Pedantic]

Ah, okay. So how good is Adata?

 

[gaidensensei]

Never tried adata myself.. always has been kingston, sandisk. Sometimes, I've seen a card that does faster than the advertised class. Luck of the draw kind of thing.

 

[shortylickens]

In my phones and camera?
Minimal.

On a USB 3 card reader?
Quite a bit.

Since I prefer thumb drives this isnt a big deal for me.
Also, my WP7 device doesnt even have a slot, so this is a minor issue for me these days. I just use the microSD card in my Droid for music.

 

[Soccerman06]

Just get a random sandisk microsd, they are better than most others. My 32gb card can do 19mb/s read 8mb/s write.

 

[runawayprisoner]

As said, a faster card is better for video recording, and sometimes for game installing/loading time.

Personally, I use a faster card mostly for my camera. The higher class cards (6 and 10) do make a difference in burst speed and while taking RAW photos.

 

[Suspicious-Teach8788]

But how much speed do you need for video recording? The bitrates for video recording on a phone aren't very high to begin with.... You only need Class 2 or something on a DSLR to do video. If anything, it takes far more horsepower to shoot RAW photos than it does to record 1080p video on my Canon 7D.

 

[Oyeve]

In my transformer and in my vibrant I have 16gb msd cards rated at class 2. I shoot video and take pictures, play music and stuff and never have I gotten a stutter. I encode dvds to mobile formats usually at 1gb file size and they playback just fine. I did the same with my class 2 8gb msd cards and see no difference. Im sure there is a gain, I just cant justify the cost premium for it.

 

[Raduque]

I have a class 4 8gb in my myTouch 4G Slide. According to SD Tools, it writes 6.5MB/s and reads at 19MB/s. It's a Sandisk. I'm going to buy a class 10 PNY 32gb, but that's because it's the second cheapest class 10 32gb card on Newegg.

 

[akugami]

The problem with saying one card is better than another simply by the speed class is that some lower classed cards actually can outperform higher classed ones. The classes are Class 2, Class 4, Class 6, Class 10. These represent the speed in MB/s.

The problem in saying one card is better than another is that it is the minimum rated speed. Not the maximum possible speed. You can have cards rated at 4 MB/s but actually can sustain 6 MB/s or higher speeds. These class speeds are not verified but quoted by the manufacturer.

Then there is an x rating. Each x rating is equal to 1.2 Mbit/s. A 66x rated card is rated at 10 MB/s. And we have further problems with the x rating because some will quote the read speed, some will quote the write speed which is typically slower.

In other words, it's a complete crapshoot how fast your memory card actually is. I'd stick to the bigger brand names to be safe.

Depending on what your phone is doing with the SD card, a faster card may speed up your phone. Example, if you're recording video and it's dumping the feed directly to the memory card, a faster card is definitely going to help a lot.

And just as there is a difference in speed between memory cards, there is also a difference in speed between readers.

 

[xSauronx]

posting since i recently put in a 16gb class 10 into my nook color to replace the 8gb class 2

booting is faster, i expect because read speeds for whatever it is looking for on the card is quicker, and opening data stored on the card is generally quicker than what it was with the class 2 card. just put it in this afternoon, so i havent yet done much with it, but a few things were noticeably faster so im happy i went that route

take that for what its worth.

 

[Mr. Pedantic]

I'll probably get a Sandisk Class 4 32GB, I'm assuming that should be enough for my phone. Considering I'm currently using a 1GB no-name Micro-SD card, it should be pretty good.

The problem with saying one card is better than another simply by the speed class is that some lower classed cards actually can outperform higher classed ones. The classes are Class 2, Class 4, Class 6, Class 10. These represent the speed in MB/s. The problem in saying one card is better than another is that it is the minimum rated speed. Not the maximum possible speed. You can have cards rated at 4 MB/s but actually can sustain 6 MB/s or higher speeds. These class speeds are not verified but quoted by the manufacturer. Then there is an x rating. Each x rating is equal to 1.2 Mbit/s. A 66x rated card is rated at 10 MB/s. And we have further problems with the x rating because some will quote the read speed, some will quote the write speed which is typically slower. In other words, it's a complete crapshoot how fast your memory card actually is. I'd stick to the bigger brand names to be safe. Depending on what your phone is doing with the SD card, a faster card may speed up your phone. Example, if you're recording video and it's dumping the feed directly to the memory card, a faster card is definitely going to help a lot. And just as there is a difference in speed between memory cards, there is also a difference in speed between readers.

Yeah, I know about the x rating, and I dislike it because it also specifies that the rating is the maximum read/write speed, not minimum. At least with the class you shouldn't ever go below a certain point.

 

[akugami]

Yeah, I know about the x rating, and I dislike it because it also specifies that the rating is the maximum read/write speed, not minimum. At least with the class you shouldn't ever go below a certain point.

Still wish there's some sort of proper testing and rating for both read and write speeds. A minimum is better as you said because you should expect at least a certain level of performance. But the Class rating is still screwed because a manufacturer can quote whatever the hell they want.