Which chipset is better?

The 800 is the sucessor to 700. They are more or less the same with a few updates. The 870 for example is a slightly improved 770. If your buying now, get the 800 series, but you wouldn't notice much of the difference for between them.

okay. thanks

im asking this because i want to buy either gigabyte 770T-USB3 or asus M4A87TD/USB3.

so, i'll take the ASUS mobo.