Upgrading PSU on Z420 Workstation

[OK_Gamer]

Hi. I have an old Z420 Workstation that I wanted to upgrade the power supply on. I was considering getting this one: https://www.newegg.com/deepcool-dq750-m-v2l-750w/p/N82E16817328018?Item=N82E16817328018&quicklink=tr..., but I wanted to make sure it is compatible because the specs sheet (https://support.hp.com/us-en/product/hp-z420-workstation/5225033/document/c03277050#AbT2) here on the HP website says that the PSU currently on the system is custom. So, does anyone know if this PSU would be compatible or if there is another one that would be?

PS: The reason that I am upgrading the PSU is that I want to install an RTX 2080, so the PSU needs to have a cable that can power a GPU, and the current PSU does not.

[DGroves]

first of all the rtx2080 is overkill for the supported cpu's the z420 can run the z2070 is a much better match

installing a 2080 is like using premium gas in a system that runs fine on regular gas the 2080 will be cpu bound in a z420

and since the 2070 draws about 170 watts the optional z420 600 watt supply can run one of these cards ,

the stock 400 watt supply is not really suitable if you run upgraded cpu's/ram/drives it's for basic minimal configurations

next the z420 does use a custom power supply, however adapters are made to convert to normal ATX supplies

note that only the early 600 watt units have two 6 pin  leads, later models only have one but this is not a issue as you can use a quality 6 to 8 pin adapter or a 6 to dual 6pin adapter for the GPU and still meet HP spec power wise

https://www.moddiy.com/products/24%252dPin-to-18%252dPin-ATX-Cable-Adapter-for-for-HP-Z420%7B47%7DZ6...

[SDH]

These HP power supplies are not built to ATX standards.  They are built higher.  Do you understand the higher wattage one of these HP power supplies provides via each PCIe supplementary power cable?

Do you understand the two different power supplies HP had for these workstations?

Do you have the higher wattage one?

Do you understand the cable pinout differences between ATX standard and the HP custom approach?

[OK_Gamer]

Thank you for the info. I believe I have the 400 W Power Supply. I know that you said that the 24-bit to 18-bit connector would allow me to use a normal PSU, but I was wondering if I would also need any other cables as well, or if that would be the only additional cable I would need. Thank you very much for your help.