Hi @shaocaholica,

Not sure what spec you're looking at.  PSU's for the 7080 MT go 260w, 360w, & 500w.  But PSU's for the 7070 MT just go as high as 360w.  PSU's listed below come from the 7070 spec sheet:

260W typical 85% Efficient PSU (80 PLUS Bronze); ENERGY STAR compliant, Active PFC 260W typical 92% Efficient PSU (80 PLUS Platinum); ENERGY STAR compliant, Active PFC 360W typical 90% Efficient PSU (80 PLUS Gold); ENERGY STAR compliant, Active PFC

By any chance did you see another spec in this forum by redxps630?

Thanks @bradthetechnut 

Does every generation of Optiplex MT break compatibility with the power supply from previous generations even tho they have the same chassis/form factor PSU?  I have a 7050 and 7040 I could see if this 360W PSU works in those as well despite those models not being shipped/spec'd with a 360W PSU.

7070 and 7050 have 6-pin MB connector.  7070 360w PSU working in a 7050 is a possibility.  7040 is 8-pin.

If you want, check out the MB images below.  Zoom in to see connectors.  Images aren't in order.

So my 460W (H460EBM-00 4FWF7) arrived.  This was listed as compatible with the 7070MT by some sellers.  I had my doubts but I gave it a shot and I can already return.

Well it didn't work.  Failed the same way the 500W (D500EPM-00 5K7J8) I got previously.  Flashing yellow power light.  System won't power on but fans spin.  The common feature between the 2 non-working PSUs is an additional 4pin motherboard power connector which has no corresponding receptacle on the 7070MT motherboard.  The PSUs that work have a 6pin+4pin(labelled P2) motherboard cable.  The PSUs that don't work have 6pin+4pin(P2)+4pin(P4).

I'm probably going to return this one but curious if it might be possible to get these higher wattage PSUs working somehow since they have additional PCIe GPU power rails.  Maybe the un-used 4pin connector needs a dummy load attached?

Does anyone know what the pin outs are on the working 360W (H360EGM-00 19YR3) and also the pin out for the non-working 460W (H460EBM-00 4FWF7) and 500W (D500EPM-00 5K7J8)?

6 pinout of 360w, 460w, 500w psu listed above are believed to be identical.

the reason why 460w and 500w psu do not work in 7070 MT is because those psu have 6+4+4 pin.  both 4 pin connectors require a load in order for the psu to work.  When one of the 4 pin connector is not plugged in motherboard, it senses no load.  The psu is designed to throw an error then.  Bad Dell.

The 360w psu works in 7070MT because it is 6+4 pin.  7070MT motherboard is 6+4 pin.

At thanks. Maybe I can put a small artificial load on the unused 4pin

One scheme I am thinking of is to convert the unused second 4 pin connector to a 6 pin PCIe and plug it in a gpu as a load.  If this would work and motherboard could boot, it would have successfully circumvented the Dell psu bad design.

4 pin cpu to 6 pin PCIe

4FWF7 04FWF7 460W PSU For Dell 3046 3040 3050 5050 MT H460EBM-00 6+4PIN - 365PowerSupply.com - Replacement Laptop Power Adapters,Desktop Power Supply & Server Workstation PSU.

Would that work?

I am also searching for a PSU. There are many 3rd party options. See:
- https://www.youtube.com/watch?v=2E1z6HwbVPY&list=PL1yjXFzHnEzcuthrnKFmILEomV4utBhhZ
- https://youtu.be/coj91go5ljc
These do require modding. Would be nice if Dell could backtrack to this and help the little guy and test some up-to 850w Power Supply. The PCs go for cheap and the CPUs are pretty good. I don't like the idea of modding my case, also I don't have metal cutting tools. Just found that I could fit a RTX 2060 small form:
https://www.msi.com/Graphics-Card/GeForce-RTX-3060-AERO-ITX-12G/Specification

https://www.pny.com/pny-geforce-rtx-3060-12gb-xlr8-gaming-revel-epic-x-rgb-sf

https://www.gigabyte.com/Graphics-Card/GV-N2060IXOC-6GD-rev-10#kf

I hope to get one of these working, as I got an R715 that I found has power issues, due to the motherboard limiting PCIe power (think due to the PCIe standard) and if I want to make that into a remote game server (for just me), I would need to use the power from my RAID and that only gets me to 75w max over all PCIe lanes (bummer). Also, wanted a large storage (at least) from this server and now am researching 2TB RAID limitations (in old BIOS), the price of large capacity 2.5" drives (wow, expensive), and why 512e drives are supported by the hardware, while 4Kn are not and if there is any way to get a large capacity NAS out of the scrap metal that work gave me. I hope one of my 2 missions pan out and I get something better than my Acer Predator 17... or at least an upgrade path (for one of the 2 or even a different case entirely) and parts that are future-proof. Looks like I am power supply hunting. Too bad I can't just take the R715 1000w PSU and stick it in this baby!

Also, I saw that many PSUs are recommended to run at half capacity for efficiency. Does this half capacity rule also go towards how likely it is to cause any issues?

I use ( LXun H360EGM-00 360W VM8KR )  for my Optiplex 7070MT   and it's work  with  ( zotac gaming geforce gtx 1650 amp core 4gb gddr6 )  and it's work  100% .

thanks .