HP Z8 G4 and 2x RTX 3090 GPU supported on 1700W PSU?

[SmileM]

Hello, I try to understand can the 2x RTX 3090 with TDP of 450W be used in HP Z8 G4 with power supply specified of supporting 1700W on 230V AC.

[DGroves]

 if the new "Z" series use a multirail type power supply

the same as the earlier z800-840 workstations had

then you cannot because rach GPU rail subsection

is only rated for 12v @ 18 amps = 216 watts

so if you also include the 75 watts the pci-e bus provides

you have a total of 291 watts for each gpu rail

i believe the 1400 watt supply only has two 6 or 8 pin power connectors

using the common 6+2 connectors although this post appears to show a 4 plug variant

https://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/HP-Z4-G4-G6-power-...

if the power supply is a single rail design where the total wattage is available on every connector,

then it might work providing you stay under the supplies total wattage for all devices (computer system and addin parts)

a single  3090 card draws  approx. 350 watts steady state when in 3d mode (and can draw/spike quite a bit higher)

https://www.electricalsafetyfirst.org.uk/watts-to-amps-calculator/

[SmileM]

The PSU has 4 GPU 6pin +2pin cables.

The PSU has 4 18A power lines from sticker you can see this.

Why cant I connect All 4 GPU power lines together, then split them to my two GPUS? The power will be shared.