First 12 V rail is 23 amps... a little bit low. That is around 276 watts of power, which your system might be overusing. You have a second rail, however I'm not 100% if you are even using the second one.
how will i know if im using a second one...and also? can the psu be bottle necking it? and if so why is it only valve/source games? BF3 sleeping dogs batman alll play fine on ultra