"another thing i heard that the heavier the psu is the better it is is that true?" - it depends from what you intend to use it... If you want to research how deeply a PSU inserts into the soil after dropping it from different hight, then yes, a heavier one should be your choice. But for general use (that for powering pcs), other parameters are more important. One exception: if you intend to carry your system (lan parties for example) a lot, you may want to go with lighter ones - but even that, the other parameters (as quality, reliability, efficiency) should be your primary focus.