What are the SD specs for my 7022?

[tink1cker]

I've searched here every way I know to for SD specs for my 7022. I know it can handle 32GB, but I need to know what class works best in this unit. I've read about HS, UHS-I and UHS-II, which I know has to do with bus width, and then I've noticed the different class speed ratings. Class 2, 4, 6 and 10. I'd like to know what is the maximum spec that's reliable for me.
Thanks for everything.

 

[nba1341]

Class 10 always

 

[Spider]

The answer to the question as asked is class 10. I may be wrong, but I think you really want to know what the minimum reliable spec is. I've seen many responses to that question that say class 4 or higher is sufficient. I myself have been using nothing but class 4 to store movies, videos, PDFs, pictures, app backups, ROM backups etc. and have never had a problem. Even when running CM7 off my SD card for a while, a class 4 worked just fine.

 

[Tom T]

Class 4 is fast enough for video, from what I have seen some firmware actually limits data transfer rate for the sd, although I've never really been able to understand why, although it seems arbitrary and can be adjusted. There isn't much point in spending more than you have to anyway, and class 4 is very inexpensive these days.

Sent from my Transformer TF101 using Android Tablet Forum

 

[Spider]

from what I have seen some firmware actually limits data transfer rate for the sd, although I've never really been able to understand why

The reason goes all the way back to the 1960's, when the first hard drives were able to cause data over-run by feeding data in at a faster rate than the mainframe processor storage could accept it. (Quite possibly, the "storage" on many of these tablets is class 4 or perhaps lower and the firmware has to limit transfer speeds to prevent over-run from occurring.)

 

[lfom]

There are some tools for benchmarking SD read/write speeds, like AnTuTu and SDTools. I compared a Class10 card in the external slot that I think I will use as internal at some point, and the speeds were higher than the internal card, i.e. the internal one is about 4MB/s while the Class10 yelded around 10MB/s.

 

[tink1cker]

So...from what Tom T says class 4 is fast enough for whatever the 7022 needs to do BUT Spider says class 10 will work. Spider, is the class 10 actually being fully utilized or is it just that it's backward-compatible in it's structure and is actually running at class 4 speed? If the 7022 will fully utilize the class 10 spec then that's what I want, but if it won't, I don't want to waste the $$$. I hope I'm being clear enough in what I'm asking. Thanks, everyone!

 

[Spider]

I'm actually recommending class 4, because it will do the job at a much lower cost than a class 10. What Tom T and I are both saying is the class 10 speed will probably not be fully utilized, as lfom's measurements indicate. Kind of like buying a Ferrari to go grocery shopping.

 

[nba1341]

class 10 is utilized even higher so by changing sd card cache size. You will notice a huge different in gallery if you have a lot of pictures.

 

[tink1cker]

So just go ahead with class 10...cuz I like fast access. Thanks for the help, guys.