There isn't really enough information to go on. Your main power draw in a machine with a discrete graphics card, is the graphics card, so if you have one (or more) or intend to buy one, it is this which will dictate how much power you need.
If you do not use a discrete graphics card, then a 650W PSU is likely to be massive overkill for your system.
Additionally -
Age will play it's part. Even the best quality PSU will age over time, as capacitors have a finite lifespan. If your PSU is say 5years+ old then it's probably a good idea to get a new one, though it will depend on how much you use the PC.
The model of your PSU will also be significant. Not all 650W PSUs are equal.
A possible limitation of an older PSU might be that it is not Haswell certified. It will still work with a Haswell system, but may not be compatible with some of the low power states.