installing a Nvidia Quadro P5000 in a Dual Xeon Z820

[Minn2000]

I have a dual Xeon HP Z820 that I'm installing a Nvidia Quadro P5000 in.  The card requires an 8 pin power cable.  There are only 6 pin cables available.  I have the larger 1125 Watt power supply.  If what I read in correct,  I can just use a HP 6pin to 8pin Power Supply Adapter (N1G35AA) to power it from the 6 pin cable correct?  I have found one although it's a little pricy but it's the HP one and I'm more comfortable with that one than some off brand.  It seems like that the correct way to do it right?  Any advice would be greatly appreciated

[NonSequitur777]

@Minn2000,

What I have done in the past in a similar situation, I used a dual 6-pin to 8-pin adapter cable.  That way, you provide sufficient power to your Nvidia Quadro P5000.

Depending on if your 6-pin cables are normal sized or mini-sized, these are two examples of each: Dual 6 Pin Female to 8 Pin Male GPU Power Adapter Cable Braided Sleeved 9 inches TeamProfitcom : Ele...or: Amazon.com: TeamProfitcom Dual Mini 6 Pin to 8 Pin PCI Express Video Card Power Adapter Braided Slee....

A single 6-pin connector can supply 75 watts of power -at least that is the nominal ATX power supply standard, but I'm pretty sure it is similar to HP's versions of their proprietary power supplies.  Anyway, an 8-pin connector can deliver 150 watt. Since your GPU requires more than 75 watt, that's why you'll need two 6-pin connectors.

[EDIT:] Yes, I tried a single 6-pin to 8-pin converter cable to power an 8-pin GPU and found that it there was too much load for the 6-pin. 

Hope this helps.

Kind Regards,

NonSequitur777

[Minn2000]

Thanks for the info.  I really appreciate it.  What I read said that with the power supply I have, the 6 pin with the adapter would be enough power, but that didn’t  seem right to me.  What you said makes a lot more sense to me.  My question is are there any down sides to combining two 6 pins into one 8 pin?  There’s no chance of it getting “too much” power correct?  That might be a stupid question, but I’m just curious if there are any dangers or down sides to doing that.  The cords in the links you sent me look pretty high quality right?  Thanks again for all your help!

[NonSequitur777]

@Minn2000,

No, there are no dangers in doing that. It is much better to have more wattage available than underpower a card. Being a dual-slot card, your Nvidia Quadro P5000 card draws its power from an 8-pin power connector, and has a power draw of 180 watt max. Even if you were to power your card, say with a dedicated 1,000 watt power supply, it would not matter.

[EDIT:] Btw, need to mention that in addition to the 2 x 6-pin power supply sources (2 x 75 watt), a PCIe X16 slot can deliver up to 75 watt too, adding this all up this provides all the power your card needs.

Kind Regards,

NonSequitur777

[Minn2000]

One last question…there’s no issue with the wiring right?  It’s all pretty standard I assume when it comes to the adapters.  By that I mean, each of the pins are uniform in the 8 pin and 6 pin.  There are no variations I would have to account for right?  Thank again for all you help and advice.

[NonSequitur777]

@Minn2000,

Nope, as you said it yourself, it's all standard. There are no issues with the wiring, these products are legit and reliable.  I think your 6-pin power connectors are standard 6-pin connectors, btw.  Anyway, I have done a lot of (creative) power rewiring -using standard power cables such as the first Amazon link I provided.  For example, here's one picture during the middle of my HP EliteDesk 800 G3 SFF upgrade project:

Link: Solved: Upgrading HP EliteDesk 800 G3 SFF - Page 5 - HP Support Community - 8251218

Kind Regards,

NonSequitur777

[DGroves]

your workstation is a custom design as such some things on it do not follow what consumer systems do

the z820 power supply is one aspect

the power supply is a multirail design not single rail, as such each rail has a specified limit in regards to power

you will note that the 1115 watt supply has three 6 pin connectors, however two of them are on the same GPU 1 circuit with the GPU-2 being on a different circuit in other words one gpu cable has 2 connectors and the other one has a single connector

ideally you want to connect the HP adapter so the dual  6 to 8 pin adapter is connected to GPU 1/2 (this way it draws power from each gpu rail) and the remaining 6 pin goes direct to the card

last. the HP adapter is the gold standard of 6-8 pin adapters as it uses thicker gauge wires, has "power chokes" and the Molex connectors are made of high quality metal/plastic

3rd party adapters range from not bad to will start a fire, due to substandard wire gauge, poor Molex connectors and you can't see visually which adapter is using wires with thinner copper lines or tell which one is using substandard connectors

[Minn2000]

Thank you for the information.  I do have a couple of questions.  With the dual 6 pin to single 8 pin, I understand to use the one "non split" cable and one of the other 2 split 6 pin cables because of the rails, but you also mentioned  "and the remaining 6 pin goes direct to the card".  There is only one 8 pin power connection on the card, so wouldn't I just leave the 3rd connector unconnected?  Also I could only find and HP 6 pin to 8 pin adapter not a dual 6 to single 8.  Based on the recommendation of the above poster I ordered this one ( https://www.amazon.com/Female-TeamProfitcom-Adapter-Braided-Sleeved/dp/B07V4GGS43/ref=sr_1_3?crid=2G... ) from Amazon.  It looked pretty good to me, not like the cheap e-bay ones.  Thanks again for your time and the information.  

[NonSequitur777]

@Minn2000,

The adapter cable you ordered is fine and is not gonna burn your PC to ashes.

But as @DGroves mentioned, connect the two 6-pin power connectors to the separate power rails, and the 8-pin to your graphics card.  That's all you have to worry about.

Kind Regards,

NonSequitur777

[Minn2000]

Lol…good ashes is not what I was going for.  The other 6 pin would just remain unconnected correct?  Sorry for all the questions..I know just enough to get myself in trouble. Thanks for everyone’s help.  This forum is great.