PSU for 7970 and i5 3570k

Hi all, i just assembled my new pc.

I have a i5 3570k (not overclocked yet), 2 x 4GB Ram corsair vengeance, 1 HD SSD 256GB Samsung 830, 1 HD Seagate barracuda 7200 RPM 1 TB, and XFX 7970 (not overclocked yet).

I am using my old PSU, cooler master silent PRO M 500W ( specifics at the bottom of this page http://www.coolermaster.com/product.php?product_id=4196... ).

It worked fine with my 5850 and core 2 duo E8500.

Now the new PC wouldn't boot up the first time cuz i only inserted 2 6pin cables in the video card.

Inserting one 6-pin and one 8-pin made it start.

Yesterday i played several games without issues.

Today PC wouldn't give video signal. Had to remove video card and power cables and reinsert it and now it's up and running.

Someone on other threads said the 12V channel should have at least 36-38A and mine has only 34A from what i see, and 408W on 12V. (Didn't find this 12V info on AMD website where i can only read that a minimum of 500W PSU is needed)

Do you think i should replace it ? Is there risk of damaging some components if i don't upgrade or i just risk instability/crashes/not booting up?

Thank you, i am not expert in PSU.