are you sure it's good? im planning that in future im upgrading my cpu to an i5 quad core and an ATI Radeon 7950 DDR5. is that psu stable for my current system or it will last for a couple of years??
The GPU is normally the single largest draw of voltage in a performance-oriented system, and if you are planning on a 7950, the PSU should be one you trust to really be up for the task. Seasonic is a great (arguably the best) PSU manufacturer on the market, and the M12 or S12 520w units are both excellent (only difference is the M is modular). It would most likely be enough to handle your future plans. However, I would seriously consider going up to the 620w Seasonic M12 or S12 models. That nets you a 12v rating increase of 8 amps, up to 48 total- which is where you really need to make sure you have enough power.
FYI, I have run a HD6850 crossfire with an overclocked Phenom X4 965 on the M12II 620w unit and wasn't breaking a sweat. That's in theory 200+ watts CPU draw and 250+ watts GPU draw- far less than your proposed future upgrades.