you can upgrade psu to the Dell 360W psu for XPS 8940 or optiplex 7080. DP/N 2VD0G

this psu has one 6 pin for gpu, and 6+2x4 pin for motherboard. for the 2x4 pin connector you only need to connect one of the two.  used one is available on eBay.

PSU
2VD0G 360w Liteon
5K7J8 500w Delta
99TPH 500w Liteon
Y7R0X 500w Chicony

You cannot because this is a sub compact unit with less than 300W power supply. Its proprietary its not standard.

There are no options for 225W GPU where 75W comes from the slot and 150W comes from PCI-E 6 pin Aux power.

Can i connect it with an external power supply?

re: Can i connect it with an external power supply?

yes you can connect an external 24/4 pin psu if you use a 24 pin to 6 pin adapter for the motherboard.

@redxps630    You should not say that the 8940 power supply works on Vostro 3888 unless you actually own this model and have tried it.

Dell Vostro 3888

•Regulatory Model D29M

•Regulatory Type D29M002

@DELL-Chris M  or @Dell-BradL  might know the correct answer but It is not clear that what you are saying is correct or even possible without catistrophic damage if you are wrong.

NOT ALL proprietary power supplies from dell fit all models when the number of pins is the same.

If that were true you could use the 8940 3080 G5 power supply on a 3070 which you CANNOT because its not wired the same.

Number of pins is not a panacea for acceptability or fitness for a particular purpose. And there is NO SUCH THING AS 6 pin or 8 pin ATX Connector on a dell proprietary power supply. There is no such standard.  Dell power supplies are closer to EPS 12v PFC with 80 percent or more efficiency vs the 70 percent non PFC of ATX.

CPU connectors are not GPU connectors.

@redxps630 

@DELL-Chris M  or @Dell-BradL  might have more information.

re: Can i connect it with an external power supply?

yes you can connect an external 24/4 pin psu if you use a 24 pin to 6 pin adapter for the motherboard.

There is no such adapter for VOSTRO 3888

This PC comes with either a 200W or 260W PSU

If there is an upgrade or adapter then post the source with documentation and information.

Just as there is no such adapter for the 8940 G5 7080.

Number of Pins on a connector DOES NOT mean it works.

It is not helpful to post non existant solutions.

CPU connectors are not GPU connectors

@speedstep​ still no solution to put an external power supply for the vostro 3888? i bought an rtx 3050 6gb for my little brother wich its not required an external power but i want to upgrade an external psu so he can run his card comfortably..you said the 24pin to 6pin does not work,is there any other solution in 2024?please if you read this or anyone have clue just answer