my sd card is I guess a class 2 card (there is no sign on it).

But actually I overclocked it to min 250 max 900.
It is stable (am currently installing lot of little apps), and running them pretty fast.

I mean, it still takes its time for example for the HAM-Hog, and browsing websites, but now I can live with it. Before it was possible that I had to wait 5 minutes and more for a page to get up (but to be honest, that website is even shitty for desktops partially!).
And I was not capable to do anything in the meantime.

Now I can interact with the page and do other things while the page is loading.
The feeling of a reacting button can be so much worth! Before, I often wanted to close the browser, but then I had to wait a minute for the button to change its color, and then another minute for the watchdog, and another minute to have it effectively closed.

Especially at work (my capo is one of those who can't wait even a sec if he doesn't have anything to do) I always became nervous starring at my phone waiting for it to load the data we are waiting for.