I've got Seasonic S12II 380W which got 324w on 12v line.
My others settings are i5 2400, 2x 4gb ram ddr3 1333mhz, and ssd
I'm wondering if i can upgrade my graphic card (hd 6670 ddr3) to hd 7870 on my current psu. I would really prefer not to buy new one cause of lack of money.
I really appreciate your help, thanks.
The 7870 is a great upgrade, especially if you find the XT version with 1536 shaders (Tahiti LE). The 7870 GHz and the rebrands 270X, 370X all have 1280 shaders and should be priced similarly, so you can treat them as equivalent.
I don't know the price of these cards used, but if you are paying over $60, you should certainly consider getting the RX460 on a sale (just saw one at $80 after rebate). This will offer FreeSync, TrueAudio, much lower power consumption and comparable performance. Plus it's a new card under warranty.