external PSU to power GPUs on a dell precision tower 7810

[marco88paris]

Hi all,

I work in a research lab and I need to change the GPUs of the dell workstation we use on one of our setups.
The new GPUs require way more power than the old ones and I'm scared the Dell PSU won't handle it.

The workstation is a Dell precision tower 7810 with a 825W Dell PSU. I've calculated the power needs of the new setup and these will be around 950W. Also the manual of the workstation (http://topics-cdn.dell.com/pdf/precision-t7810-workstation_Owner's%20Manual_en-us.pdf) states that the GPUs installed should not require more than 250W each. The GPUs I will be using (http://www.gigabyte.com/products/product-page.aspx?pid=5560#sp) may indeed require more: gigabytes exagerates saying 600W each...

Therefore, I have two solutions (this machine sits in a research labs therefore it is completely OK if it will have to stay wide open with custom-built extensions and cables everywhere):
1) change the PSU for the whole machine
2) use a second PSU only for the GPUs

Solution #1 would make more sense but I'm struggling finding precise information about the power requirements of the dell motherboard. I know that in some cases dell uses specific connectors and voltages and I do not want at all to burn my system. Does anybody has some information about this ? the only info I find online are for very old dell workstations and do not seem to apply anymore.
The motherboard has:
- a 24pin connector that I hope has standard wiring and voltages.
- two CPU power connectors that are 10pin (I figure that the standard is 8?)

Therefore, in order not to burn my system I would like to keep powering the motherboard and CPUs with the Dell PSU and use a separate PSU just for the GPUs. I mean only the 8pin extra connectors on the top of the GPUs. But the PCIe slot feeds power to the GPU too. Will this be safe or will I fry the GPUs? Of course the PSU will not be identical...

I'm really struggling understanding which is the safest option here. Any help is greatly appreciated!

 

[Archgaull]

When the Gigabyte website says power required: 600 Watts, they don't mean the GTX 980ti alone pulls 600 watts. The GTX 980ti actually pulls only 250 Watts, when it says 600 Watts, it means they recommend a power supply of at least 600 watts, which you exceed.

Since the manual says don't exceed 250 watts for the power supply, you should be fine, since the power requirement of a GTX 980ti is 250 watts.

http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-980-ti/specifications

That shows the power requirements.

 

[marco88paris]

When the Gigabyte website says power required: 600 Watts, they don't mean the GTX 980ti alone pulls 600 watts. The GTX 980ti actually pulls only 250 Watts, when it says 600 Watts, it means they recommend a power supply of at least 600 watts, which you exceed.

Since the manual says don't exceed 250 watts for the power supply, you should be fine, since the power requirement of a GTX 980ti is 250 watts.

http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-980-ti/specifications

That shows the power requirements.

Thanks for your fast answer!

This should semplify things enourmously. But I'm reading now the manual again and it says "up to 2 full-height, full-length (maximum of single 225 W)". I did not remember correctly. And I have plenty of other hardware installed on the machine. If I calculate the power necessity with this (http://outervision.com/power-supply-calculator) I obtain 908W. The dell PSU is 825W.
Will this work anyway?

Also:
for PCIe GPUs, the dell PSU comes with a 8pin connector + a cable splitting this one into 2 6 pin connectors. For my GPUs I will need four 8pin connectors. Can I therefore double each 6 pin connector with a splitter cable and then tranform each 6pin end into a 8pin one with an adapter?

Many thanks again for your help!