I'm not really good with psus but the max load on +12V is 38a according to the box I have before my eyes, so then I guess its 38 amps version?
ok, there are a few different CX500s floating around in different parts of the world; just checking.
just an FYI, a 7950 can get up to 200 watts with a crazy overclock; it would depend how high you have to set the voltage when overclocking. a 965 BE can get up to 175 watts ( +50 more than stock) which again depends on what voltage you need to keep it stable.
the 375 watts for just the gpu and cpu, not adding in the chipset, RAM and hard drive needs (~35 watts), is pushing that "max" power of 456 watts pretty close. oyu can run a 7950 "out of the box and overclock the cpu to keep it from being a bottleneck. but if you are looking to overclock that 7950 also, a 550 -650 watt PSU would be most desirable.