AMD Quad-Core A8-4500M 1.9GHz or Intel Core i5 3210M 2.5GHz

The i5 is a faster CPU. The A8 has a faster on-board GPU.

If the i5 has a discrete GPU, it will probably be a better gamer (depending on which GPU). If not, the A8 will be a better gamer.

Is there any reason why you want a laptop for gaming? Are you trying to decide between two specific ones?

i don't know what to decide between these two:
http://www.vexio.ro/notebook-hp-pavilion-g6-2011sq-inte...
and
http://www.altex.ro/laptop-hp-pavilion-m6-1060sq-amd-qu...

The first one, easy. It's cheaper and has the better CPU. They both have the same 7670M GPU.