11 Posts
0
4989
T7810 with 1300W power supply
Hello,
This unit, as described in title, offers two 10-pin CPU power connections. I want to plug devices requiring peak power up to 360W from a CPU connection (not PCIe power connection). Is there any reason I will not get this power from the CPU connection?
Thank you for your help.
Tryphon Cosinus
11 Posts
1
July 18th, 2021 06:00
Hello,
I made some tests to understand the rail configuration on my PSUs : Dell 685 and 1300 W. The sticker on the top lists 5 and 10 rails respectively.
Both PSUs work like a charm in my T7810 workstation.
The distribution board I have to power my T7810 cannot use all the rails provided by the 1300 W PSU. In that way, the 685 W PSU is preferable for my configuration.
For example, the T7600 workstation may fully use the 1300 W PSU. I have a distribution board for it.
In both distribution boards, the rails are connected to the pins identified A1 to A32 and some from B1 to B32. At least 18 lines in B are connected to the ground. Power is mainly provided by A lines. A lines are grouped to power the connectors on the distribution board.
In the T7810 distribution board, for example, the P1 connector uses 2 set of lines : 5 pins for the ground ans 3 pins connected to A9-11 lines. A9-11 lines seems to form an independent power source dedicated to feed a video card. This distribution board does not use A12-14 and A29-32 power sets. However they are used on the T7600 distribution board to feed a video card and one of the CPUs.
From the T7810 distribution board, I see 7 power sets but the 685 W PSU has only 5 rails. From the T7600 distribution board, I see 10 power sets and 1300 W PSU has 10 rails. I do not know what is the exact relation between a rail and a power set.
If A12-14 and A29-32 power sets are matching 2 rails, I would expect to get 2 x 12V x 18 A = 432 W.
I plugged a Tesla k80 card using extra wires soldered on A12-14 and A29-32 and mounted in a 8-pin EPS plug that fits in this device. Precisely A12-14 pins connect pins 7 and 8, and A25-28 pins connect pins 5 and 6 on the Tesla board (https://www.nvidia.com/content/dam/en-zz/Solutions/Data-Center/tesla-product-literature/Tesla-K80-BoardSpec-07317-001-v05.pdf). On the Tesla side, the EPS connector requires 225 W. I hypothetized that A12-14 plus A25-28 may feed 432 W.
Result with the 1300 W PSU. When the Tesla card is seated in a 16X PCIe slot without plugging my extra EPS plug, the T7810 starts normally (of course, in that way, I cannot use the card). When I plug this extra cable, the PSU seems to continuously restart (nothing appears on the screen, I cannot reach the BIOS and no beep is emitted). Note : "Memory Map IO above 4GB" is set in the BIOS.
Despite of the fact this result is frustrating after so much effort, I wonder if someone may bring any information or point any error that may help me to reach my goal to have the Tesla k80 card powered correctly.
Thank you for your help.
speedstep
9 Legend
9 Legend
•
47K Posts
0
December 13th, 2020 06:00
The connections you reference are from a daughter board.
If you do not have the cables its game over.
@DELL-Chris M might have more information YMMV
YFY1V - 425W PSU
VDY4N - 685W PN: W4DTF K8CDY CYP9P WPVG2 KTMT8
RHHKV - 825W PSU (Not sure if the chassis is the same)
(Not sure if the chassis is the same)
v5K16 - 1300W PSU ( chassis is the same???)
MF4N5 - 1300W PSU
OT6R7 - 1300W PSU
T31JM - 1300W PSU (Not sure if the chassis is the same)
https://www.amazon.com/Power-Supply-Precision-T5810-Workstation/dp/B0777NYWLL
Tryphon Cosinus
11 Posts
0
December 13th, 2020 19:00
Great to have more details. My power supply has reference 05K16. The daughter board is a bit different for the T7810 as CPU connectors are 10-pin and not 8-pin.
Yes, the cable I need is not sold anywhere. However, it is not so complicated to assemble one if I could know the schematics to convert 10-pin cpu connector (male) to standard 8-pin cpu connector (male). Maybe, two of the five 12 V wires has to be merged. Any advise ?
Thank you.
Tryphon Cosinus
11 Posts
1
August 8th, 2021 06:00
Finally it works with this PSU. The main setting to add in Bios is to force PCIe link speed, I think. Otherwise another of my post elsewhere in the net explained this with more details.
Thanks.
karlcchen
5 Posts
0
May 17th, 2022 13:00
Very helpful info for my T5810 with NVIDIA RTX-3090 Ti which required three pcie-9-pin connectors, each one can draw 150W for a total of 450W. I got a new 1300W PSU for this.
I found original two pcie 6-pin connectors is only good for one input to RTX 3090
I need two more pcie 8-pins connectors, I am taking them from the 2nd CPU power connectors.
It is working, but I think getting them from A12-A14 and A29-A31 is better if they are unused.
Thanks,
Karl
Tryphon Cosinus
11 Posts
0
June 13th, 2022 10:00
Hello,
Sure you cannot use a second CPU with this setup. I provided details here to describe what I did. Now I also use B29-B32 pins to feed a third video card. The configuration remains stable to process heavy matlab code. Could you tell what OS you use?