where to find 24 Pin ATX to 6 Pin HP Adapter Cable for prodesk 400 G5 minitower?

[gamernoob5]

i bought this computer from a friend but i didn't know that it's an OEM/proprietary at the time and that it would not work with a third party PSU. now i need a PSU cable adapter but i'm having trouble finding one for it, i found this one but it did not list my exact computer model and my model has 2 white connectors that have 4 pins and square-shaped which i believe are for the CPU? i was worried i might damage the mobo if i try and see if it works  https://www.amazon.com/24-pin-6-HP/dp/B0CYBS1WZ5?th=1

any help? am buying it so i can replace the PSU with a 500 watt one and use a graphic card with it (RX 590)

note:

[NonSequitur777]

@gamernoob5,

Welcome to our HP Community forum!

Unfortunately, there is no ATX power adapter available for your HP ProDesk 400 G5 Microtower.

Based on cross-compatibility (HP ProDesk 600 G4 MT), I believe that this HP proprietary 500-watt power supply with part number: 901759-013 should be compatible, as shown here, for example: https://www.ebay.com/itm/204305683347?_skw=901759-013&itmmeta=01JT6AKXTX5JFRCCAPB9ZP66Y1&hash=item2f....

The 7-pin "P2" power connector looks the same as the one from your stock power supply.

Kind Regards,

NonSequitur777

[gamernoob5]

so is there no way to make the proprietary PSUs work with a dedicated gpu then? darn it, i only bought this computer so i could use it with a dedicated gpu as a budget alternative cuz i was told i can just workaround it with an adapter. thank you for the help tho. seems like i was misinformed by my friend 

[NonSequitur777]

@gamernoob5,

The HP proprietary power supplies are the ONLY way to make a dedicated graphics card work in your PC vs. the industry standard ATX power supplies cannot be made to work in your PC.

Kind Regards,

NonSequitur777