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
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.
Be alert for scammers posting fake support phone numbers and/or email addresses on the community. If you think you have received a fake HP Support message, please report it to us by clicking on "Flag Post".