XPS 8950, power connector pinout diagram?

Excellent. Much appreciated! Thankfully, Corsair have an old standard 24-pin to new standard 10-pin ATX12VO adapter cable available for purchase (part number CP-8920272) so can connect a standard PSU. Just so happens that i have a new Corsair RM750x 2021 model PSU i can use, but should think that Corsair's adapter cable would work with any PSU that only has the standard 24-pin ATX motherboard connector cable, and would also imagine that the likes of modDIY and COmeap will soon make identical adapter cables available for purchase.

***UPDATE*** Just realised that the Corsair standard ATX to ATX12VO adapter cable won't work because sneaky Dell have slightly changed the shape of some of the individual pin sockets (pins 4, 8 and 9) on their motherboard connector block (see photo) which makes it slightly different from the standard ATX12VO connector and so prevents the use of a non-Dell power supply, forcing you to buy one of their expensive PSU's instead if, like me, you want to upgrade from the 460W PSU in the 8950 (i was looking to plug in a Corsair RM750x PSU that i happen to have and just have it outside of the case). Is looking like i'll just have keep the Dell PSU connected to power the motherboard, and use a second PSU just for powering my RTX 3080 GPU.

this may be a good thing as the plot thickens. need to further investigate Dell's proprietary pinout before saying for sure it is ATX12VO standard.  

another 8950 user reports Dell 460w psu for 8950 has only 8 pins, although motherboard connector socket is 10 pins.  This makes one wonder how many pins the Dell 750w psu would have (?10).

if you can confirm the 460w has 8 pins only, then it makes sense Dell (sneaky as you said) designed the socket in a way that prevents incorrect plugging of 8 pin connector.  In other words, Dell made the 10 pin socket asymmetric (as shown in your good photo) such that the 8 pin connector has only one way to be plugged in.  this is actually quite important in Dell factory pre-assembly.

I suspect Dell is indeed using only 8 pin 460w psu because in the new inspiron 3910 of 12th gen cpu (which uses 180, 240, 300w psu), the mobo has only 8 pin socket.

therefore before saying ATX12VO, one needs to figure out the 8 pin proprietary pinout first.

I believe the 8 pin in red outline is actually used for the 460w psu.

89503910

Inspiron 3910

In this still photo from a youtube video, this guy has the top of the range options on his 8950 with the I9 processor and RTX 3090 GPU, which would require the 750W Platinum PSU option to provide sufficient system power... and the power connector on it looks like it fills all 10 pins on his motherboard (my 460W power supply doesn't use the two pins on the far left of the motherboard connector).

In this 2nd still photo from the same youtube video, you can clearly see that his Dell 750W PSU is filling the the last 2 pins on the left of the power connector socket... unlike my Dell 460W PSU

very strange way Dell does to psu.  Dell's way to cut cost wherever it can.  it is cheaper to make/wire 8 pin connector for low power psu.  could it be Dell went back to use the old 8 pinout of 9020/7040?

8 pin for 460w psu

10 pin for 750w psu

seems 10 pin might be sending one more 12V to the 8 pin (if it were ATX12VO pin10).  but why?  the additional power should go to the PCIe 6/8 pin connectors.  why would you need to send more 12V to motherboard?  there are already two 4 pin cpu connectors.

will have to wait for moddiy etc. to figure out a 24 to 8 pin adapter if one plans to use non-Dell psu outside the case. this may take a long time.  although the 8 pin connector of 460w psu has the same key as optiplex 9020, no way to tell if pinout is identical.  if you or someone can measure the 8 pin voltage of the 460w psu it would help to determine if the old 24 to 8 pin adapter is applicable to 8950.

When i bought my XPS 8950 in the January sale, i had no ability to customize the various hardware options. Instead i had to just select a fixed pre-built 8950 from what was available. While researching which one to get, i noticed that they all used the 460W PSU up as far as (and including) the RTX 3070ti pre-built XPS 8950's that were available.

The RTX 3070ti GPU draws a max of 290W, so can get away with using the 460W PSU. However the RTX 3080 GPU draws 320W-350W of power, and both the RTX 3080ti and RTX 3090 draw a max of 350W of power, hence the need for the 750W PSU in those versions of the XPS 8950 that come with those very powerful GPU's installed.

Now the CPU has it's own 4-pin power connectors directly from the PSU, and the graphics card also gets it's power directly from the PSU via the 6+2 PCIe connectors. However i believe some power is also delivered to the graphics card through the PCIe x16 graphics card slot (up to 95W max, i think?). I'm wondering if the 750W PSU delivers additional power to the PCIe x16 slot by using all 10 pins on the motherboard power connector instead of just 8 pins as used by the 460W PSU?. I'm just guessing though. The extra 2 pins may just be additional signal pinouts. It's a bit of a mystery for sure. 

This photo shows Dell 460w psu (8pin) leaving left 2 pin of motherboard 10 pin socket exposed.

Yes that's the same as mine. My 460w PSU only uses 8 of the 10 pins, with the 2 pins on the far left of the connector remaining unused. Only the 750w PSU uses all 10 pins,  so the question is, what does the 750w PSU use those other 2 pins for?

My particular Dell 460w PSU is this one - PNWT1 460W Bronze made by Acbel.

I've done a little digging and these are the others that are used in XPS 8950:

MP23Y 750W, Acbel
M92DC 750W, Chicony
M92DC 750W, Chicony
M2G8X 750W, LiteOn
PNWT1 460W Bronze, Acbel
389MC 460W Bronze, Chicony
T63HC 460W Bronze, Huntkey

If someone knows which other Dell PC's use these particular PSU's, then there might be a motherboard pinout diagram available for that PC and so give us a clue?  

Same psu used for Aurora R13 R14.

currently 750W psu is $50 more than the 460w on Dell 8950 config site. I recommend get the 750w one.

these OEM psu are so new that not a single photo of its form factor and connectors available on google search.

Yeah, too late for that as i already have my 8950, plus wasn't allowed to chop and change what hardware options i could have anyway as it was bought as-is in the Dell January sale here in the UK.

The only post-sale upgrades currently available to buy from Dell for the 8950 is memory... and that's it! No 750W PSU upgrade i can buy or the CPU water cooler upgrade either, so i'm stuck with the 460W PSU that came installed and that's that. Besides, i would prefer to use my Corsair PSU with its 10 year warranty anyway, or a EVGA or Seasonic PSU as i'm familiar with these top PSU brands. To be honest i've never heard of OEM brands like Acbel or Chicony. I had a look on their websites anyway and found none of the PSU models that Dell are using, so can't even buy direct from them either.

I think this is a dead end, at least for now. I guess i'll just have to keep the 460W PSU where it is in the chassis, connected to the motherboard, and use my Corsair PSU outside the chassis just to provide power to my RTX 3080 via the two PCIe power cables, which i'll  thread in through the back of the case (will remove one of the blanking plates).   

Does this old Dell CPU 10 pin connector (I believe it is 12V only for CPU) look familiar?  the key of the proprietary connector looks identical to 8950 10 pin socket.

Dell is pulling this design out of a very old 2005 XPS playbook and rehashing it in 2022.

the old pinout is

Yes, looks like that old connector block is indeed exactly the same one that Dell has chosen to use on the new XPS 8950. Problem is, the wiring pinouts appear to be completely different, with different colours and even different thicknesses (see images below).

thank you for the picture.  one step closer.

we know very likely Dell is using a proprietary modified 12VO pinout. color of Dell psu wire is nonstandard but based on prior Dell 8 pin and 6 pin 12VO psu, speculation:

brown = +12V (voltage sensing pin) (Dell has been using brown for +12V in PCIe 6 pin)

black, black = GND (Dell has always used black for GND)

the remaining 5 wires include 12V, 12VSB (one only), PWR_OK (one only), PS_ON (one only).

a good guess is:

red = +12VSB

gray =  PWR_OK  (gray has been consistently assigned to this pin)

blue = PS_ON

purple, purple = +12V, +12V (opposite black, black/GND, GND)

it seems Dell proprietary 8 pin has all the ATX12VO pins except one GND + one reserved

So do you think that the Z690 motherboard used in the new Dell XPS 8950 uses the standard ATX12VO 10-pin wiring layout, but it's just that Dell have decided to use one of their old non-standard 10-pin plastic connector blocks which has different key shapes on it?

Or is the actual 10-pin wiring layout used on Dell's ATX12VO Z690 motherboard also different from the standard ATX12VO wiring layout too, in addition to the different shaped connector block?