Well I think you might be right Daniel as the one you have got I would use as a general use one.
Anyway I have asked the others for some help on this and some of those folks are better qualified than I to advise you. So just hang on until you can get some clarification on exactly what you want. Bear in mind a larger GPU will need more power and it would be worth taking a look at the PSU you are using to see just what it can handle. to find that you can use this
OuterVision Power Supply Calculator