If I may pitch in while Digerati is offline!
Always welcome! Whether on or off-line.
If she already bought that PSU, then you may be stuck with it, and frankly, it may work just fine. I hope so. The fact it is not 80-Plus certified would be a concern for me. No power supply has a linear efficiency rating (equally efficient across all expected loads). Typically, their peak efficiency occurs at just one or two points across their expected load range. That is, for a typical budget PSU, it may have a 70% efficiency at 60% load, then drop significantly on either side of that load (for example, when idling or when pushed to fully loaded).
70% efficiency means for every 100 watts the PSU draws from the wall, 30 watts are wasted (in form of heat). In order for a PSU to be 80-Plus certified, it must have a [near] linear and high
(80% or higher) efficiency across its entire expected load (20%, 50% and 100% of rated load is the testing standard). In order for a PSU to obtain these high and linear efficiency ratings, the PSU must be well designed AND
use quality (tighter tolerances) parts. And better design with quality parts typically means a PSU that provides clean stable power.
So while an 80-Plus PSU may cost more initially, the savings in electricity costs are typically easily recouped (and more) over the life of the PSU.
Her pc is pretty basic and so i went for 500watts just to make sure as the minimum spec for the graphics card was 400watts.
And that's fine, but please understand that quantity has nothing to do with quality. I would much rather have a 500W 80-Plus certified Corsair than a 600W off-brand that is not 80-Plus certified.