I bought a $8 Samsung knockoff 32GB micro SD card, class 10. It's acting weirdly, like if I use an usb adapter, and copy some files to it, when I put it back in my Lenovo P780, some of the files disappear or get corrupted... or when I test the writing speed on the phone it's 5-6 mbps, with the usb adapter I only can move files with 2-3 mbps, and when I copy files to the card by connecting the phone to my PC via the original cable, the writing speed is 500 kpbs tops (oddly enough, when I start the copying it starts at 4-5 mbps but then in seconds the speed decreases)
I have read many posts about it online, some said that I should try SD booster apps for android (they didn't work at all) or use the PC software Teracopy to copy files (didn't work) or format it using the HP formatting tool (took me 7 hours, but no luck with it neither) and I almost gave up. This is my last try. If anyone has a solution to magicly turn this thing's writing speed to at least 1 mbps, please, feel free to tell me.
PS: Please don't waste my time telling me "you should have bought an expensive SD card, blah blah..." because it's kinda obvious I don't have any money to spend on stuff like this.