Question How can I test/push my computer's power draw to its limit?


Mar 26, 2015
I have some old dell optiplex-es (optipli?) and I'm trying to upgrade them with some graphics cards.
The trouble is that these old machines have these specialized power supplies that have really low outputs, and I can't find specs on exactly how much power the existing hardware draws, so I don't know if some of the cards I want to install would draw too much power and thus could crash the system.

I want to know what would be the best way to test these systems for how much power they draw, or moreover, if they can provide enough power to run everything with the cards I'm looking to add.

There are two cards in particular I am looking to add, both of which I already have at least one on hand that I can test with, but I want to make sure the system can handle it before I buy more of these cards to install permanently.
The best method I can think of off hand is to just run some games and see if they crash, but that seems rather insufficient, because I have no way to know exactly what game will really push the system, nor at what point the system would "spike." I might be able to run a game very smoothly for an hour at home with no problems simply because I never quite triggered the circumstances that would truly tax the system.

Plus, since there is the possibility that overloading the power supply might damage some of the components, I would be interested in finding a safer way to find out how much this system can draw that wouldn't involve just pushing everything to its limit.

Side note, if anyone knows how to find more of these weird L-shaped power supplies, I'd like to know. I don't know what they would be called, so I don't know where to look, so I don't have any idea if it is possible to upgrade the power supply, or what that would cost.
Unless you find some specs, you have no way to know that.

Replace "PSU" with your utility (or fuse box), and "components" with your house - you have no way, with existing appliances, determine how much you can draw from the utility, even if you turn on all heaters / ovens / etc in the house.