Dimension 530s Power Change Supply Size?

The biggest reason would be adding a more up to date video card, as they are use the most power. IF only adding a couple of extra drives there would be no reason to upgrade it.

I have a Dimension 530s that's several years old now. I was researching its power supply size online since I wanted to determine how many watts it uses. It looks as if the standard power supply that ships with the system is 250 watts but in finding this out, I discovered that there are power supply upgrades for this system, i.e. 280 watt, 300 watt and 400 watt. What would be the benefits/risks of upgrading from the current power supply size? I could see maybe doing it if I were adding additional hard drives to the chassis but beyond that, I don't see why one would need to add up to an additional 150 watts to the existing watt rating. Thanks for any feedback.

As per what davet50 said, also an extra HD will not consume a lot, so no need to buy a new power supply unit. That system should be a Inspiron 530s, you can still get a good card to run off your 250w PSU.