QUOTE(korn @ Nov 28 2015, 09:55 AM)
That justify the pricing difference. Not really recording 4K, just a normal use on smartphone(Redmi Note 2 & Redmi 2). Let say taking picture, burst mode - is it better to use the former, because the phone can write & read the micro SD fast? or the phone using RAM first then write it on micro SD?
So much to learn this micro SD

Typically for media storage(picture, audio, video), typically the higher the better but it really depends on what do you want to do. For 1080p class 10 and above is recommended. But still, for hardware, it takes both parties to click. If your phone cannot support that high speed, you buy a super gooding sd card also no use

. But then, how to determine the speed of your phone's sdcard slot is another story. If you want to store apps and games inside it too, then that will be another story too
QUOTE(korn @ Nov 28 2015, 10:59 AM)
I normally buy from taobao