6pin to 8 pin for z420

[gyzen]

i got a rx580 8gb for my gpu and it needs a 8pin. The psu in the z420 does not have one so i was searching around and i found out that you can do dual 6 pin to 8pin. i was goign to buy it when i reailsed i dont have a second pcie cable i only got one. i have a 600w psu rev 6, what should i do and what should i buy (other than a new psu)

[SDH · Accepted solution]

This has been posted about numerous times here on this forum, but let's do it again...

HP designs its power supplies for their workstations, such as your Z420, to higher standards than "ATX standards". 

Thus, their PCIe supplemental 6-wire power cable coming out of the power supply is rated for significantly higher than the ATX standard of 75W.  Instead of that, HP engineered in 18A of 12VDC capacity....   Power = I x V.   Watts = 18 x 12 = 216 Watts.

Thus your one HP PCIe 6-wire supplemental power cables can easily supply more wattage than two ATX standard PCIe supplemental cables.

HP makes special 6-pin to 8-pin adapters to pull this off... thicker wires, better quality interconnects. Truly 6 thick wires... The key thing to know is that you need to get one of HP's quality, not some cheap adapter. Those adapters also have been posted about here, including their HP part numbers. Don't get a no-name generic low price one if you want to do it right and have it work.

Note that there are different power supplies for the Z420... personally I always upgraded to the HP 600W good one if I was building up a Z420 v2 to be a powerful workstation, and those have two supplemental PCIe power cables.

We're still using those workstations with nice fast v2 processors and 1866 memory... did that with over 50 now and have had exactly zero failures 4 years later.

[SDH]

Here's the power supply I'd use... roughly 35.00 including US shipping currently from eBay.

[gyzen]

sorry for asking, also the g2 cable is marked on my PSU but not available.is this a mistake or

[SDH]

Use google... this also has been posted on in the past. The earlier higher power ones had two and the later higher power ones had 1 to cut some costs. The low power one is underpowered for our needs, but we've never needed two PCIe supplemental power cables in our builds once we understood the HP engineering behind the amperage and their adapters. Note in the pic I attached that particular power supply is Rev. 5.

Maybe you have a later one with an earlier label stuck on it during the transition, or maybe the pinouts for the second one are still there inside so the internal circuitry shown on the label is unchanged. The point is you have enough power to run that card with one. If you must have two search eBay and look for one with two, and tell the seller you must have what is in the picture and why.

You can find a lot of this older information with google but not with the forum's search engine. Use that to find the part numbers for that HP adapter.