A:Answer If you've got an HP with PCI-E slot, you may be able to replace your existing card with this one. However, this RX-580 card takes more power (185W max) than the pci-e slot provides (max power of 75W). The card comes with an adapter to allow you to combine open connectors to supply additional power, but your HP might not have any spare connectors, and there may not be enough margin in the power supply to provide the needed power to this card. In that case, it may require replacing your existing power supply also.
To figure it out--add the power demand of your CPU (look on HP's website/CPU website) to the power demand of this card to determine how much power is needed. keep in mind that the rating on the 12 volt is what's being tested here--not total power supply rating. So, if your existing CPU is 95 watts, this is 185; you would need at least 280 watts of power on the 12 volts line of the power supply. If the power supply lists at least 25 Amps at 12 volts (12 Volts x 25 Amps = 300 watts) it would work in this hypothetical case.
Also note this is assuming that some other device in the box isn't using 12V power for anything (like a BluRay disc or motherboard). If the graphics card wants more power than you have, you'll probably shut down in the middle of heavy gaming. So, it's best to check on that before you buy this card.
