Video card power connector question

jamesdsimone · Saturday at 3:13 PM

I wasn't sure if I should post this in the graphic card section or power supply so feel free to move it if necessary. That being said. I want to put a 2x8 pin video card in my z840. The computer has an 1125w power supply with 3 6 pin GPU power connectors. I have a 6+8 pin card in it now with a 2 6 pin to 1 8 pin adapter cable in the GPU's 8 pin connection and the other 6 pin connected to the 6 pin connection. I have read that the HP z840 6 pin connectors put out sufficient wattage to use as an 8 pin with an adapter cable. Not sure why they didn't use a 6+2 setup but that is typical these companies. My question is should I use all 3 of the 6 pins?

Shmee · Sunday at 6:35 AM

What video card is this? Obviously the PSU setup isn't ideal, but using 2x6pins to the 8 pin and the other 6 pin to the 6pin should work. If you had a 2x8pin card, you would likely be in trouble. Those 6 pin connectors are rated for 75W where the 8 pins are rated for 150W.

Again I would be cautious using so many adapters. But then this may also depend on what GPUs we are looking at, and the age/quality of the workstation PSU.

jamesdsimone · 2025-03-31T18:45:33-0400

Shmee said:
What video card is this? Obviously the PSU setup isn't ideal, but using 2x6pins to the 8 pin and the other 6 pin to the 6pin should work. If you had a 2x8pin card, you would likely be in trouble. Those 6 pin connectors are rated for 75W where the 8 pins are rated for 150W.

Again I would be cautious using so many adapters. But then this may also depend on what GPUs we are looking at, and the age/quality of the workstation PSU.

The 75/150w rating are for standard ATX power supplies. The HP's 6 pin are supposed to support 18A but I haven't been able to confirm the wattage. I have read that they put out more than the standard 75w but the HP documentation is poor.

bba-tcg · 2025-03-31T21:38:18-0400

jamesdsimone said:
The 75/150w rating are for standard ATX power supplies. The HP's 6 pin are supposed to support 18A but I haven't been able to confirm the wattage. I have read that they put out more than the standard 75w but the HP documentation is poor.

Wattage is amps x volts. So, if it's 18 amps on 12 volt rail, it can put out 196 watts (max).

jamesdsimone · 2025-03-31T23:44:33-0400

bba-tcg said:
Wattage is amps x volts. So, if it's 18 amps on 12 volt rail, it can put out 196 watts (max).

216w I think. That is what I have read. So there shouldn't be a problem. I'm being extra cautious. HP makes all kinds of annoying proprietary hardware decisions. The next generation Z4's went to 6+2 pin connectors.

bba-tcg · 2025-04-01T11:48:29-0400

jamesdsimone said:
216w I think. That is what I have read. So there shouldn't be a problem. I'm being extra cautious. HP makes all kinds of annoying proprietary hardware decisions. The next generation Z4's went to 6+2 pin connectors.

Mea culpa. You are correct.

Video card power connector question

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Shmee

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