how to connect 4 monitors to my desk top vostro 3710 i7,

Graphics card typically disables onboard graphics.

Quadro P1000 has 4 mini-DP ports with 4 mini-DP to full size DP adapters.

You may be able to use onboard gpu and discrete gpu simultaneously on Vostro 3710

https://www.dell.com/support/manuals/en-us/vostro-3710-desktop/vostro-3710-service-manual/system-setup-options?guid=guid-231220a1-ef22-4cf9-a241-dacd209540cb&lang=en-us

bios:

Vostro and Inspiron small desktop do not have options of discrete oem gpu b/c they are entry level consumer model with weak 180w psu only. But you can try install Dell oem low profile gpu designed for Optiplex SFF in Vostro 3710 (SFF).  3710 180w psu may need to be upgraded to support discrete gpu.  psu upgrade need to fit the SFF chassis.  In this regard consider 240/260w psu of Optiplex 7000 SFF.

Dell R5 430 low profile has two DP ports.

see list below.

Optiplex 3060 SFF validated Dell OEM video cards when using our OEM 200W/260W PSU =

9G0TG AMD Radeon R5-430 OU14L, 2GB, Low Profile, DP/DP, 50W


K6T46 AMD Radeon R5-430 OUGA14, 2GB, Low Profile, DP/DP, 50W

9VHW0 AMD Radeon R5-430 OUGA14L, 2GB, Low Profile, DP/DP, 50W

CNRTY Nvidia GeForce GT 730 OU14LN, 2GB, Low Profile, DP/DP, 30W

Quadro P1000 = 47w.

If you only need DX 11_2

Nvidia Quadro K1200 will do teh job for 4 monitors

If you need a minimum of DX 12

Nvidia Quadro P600 or P1000

    OR

Vision Tek AMD Radeon RX560 low profile

VisionTek Radeon RX 560 4GB GGDR5 Graphics Card (901278) | eBay

I wouldn't recommend a 75w card (RX 560) for a 180w PSU.

@bradthetechnut​  the i7 12th gen is rated for 65 watts. The graphics card is rated for 75 watts. That is 140watts total. Account for 10watts needed for mobo and ram. That is a grand total of 150 watts of the 180watt maximum. So the PSU has 17% head room.

Also if a 75watt card wasnt allowable. Dell would derate the PCIE X16 for 55watt not 75 watts.

SSD, HDD, and/or M.2?

Wifi/BT card?

DVD drive?

USB slots?

@bradthetechnut​  that is MOBO and RAM (MOBO) meaning all of the USB powered devices.

FACT is the CPU will not continuously have a load at 65 watts. FACT is the GPU will not continuously have a load at 75watts. Even USB devices aren't continuous. If all the devices were continuous duty, I would somewhat agree that the power demand would eventually fatigue the PSU but that simply isnt the case here.

CMOS/Bios also has power management cycling so even if you have a 65 watt processor there are conservative power limitations with bios micro instruction such as intel speed stepping. Even with speed stepping off intel chips are far more conservative on power draw and max power demands then AMD processors.

GPU’s also for the most part. While being rated at a 75watt max. Never show that in the bench marks usually because of thermal throttle backing the higher the GPU temperature the lower the watt output as it degrades as Celsius/Farenheit rises. Also consider over clocking. Even though the capacitors on the GPU offer the 75watt rating, lowering voltage to achieve higher clocks means it is using less voltage to reach higher threshold holds continuously at higher duty, lesser voltage.

I have a Dell Optiplex with 6th gen i7 and an RX6400 had it for 3 years now with no over heating, firea, and at the wall the AC power meter barely breaks 128watts. 

The opriplex mobos for the most part are same as the vostros.

The only concern should only be performance degredation via thermal throttling. But if dell rates the PCIEX16 slot for 75 watts and the PSU was rated for 180watts. Dell already factored al that in. For safety purposes if the PSU cant handle the rating Dell would of limited the PCIEX16 slot to 55 watts which dell has infact done in the past with lower watt PSU systems.

"I have a Dell Optiplex with 6th gen i7 and an RX6400 had it for 3 years now with no over heating, firea, and at the wall the AC power meter barely breaks 128watts."  3 yr. old RX 6400 is only 50w.

@bradthetechnut​ Your saying that the entire computer is one huge induced transient power spike at 180watts and a 75watt card is too much for the system.  After both UL and CE engineering firms stamp and approve Dell parts to meet that standard.

FACT: the PCIEX16 is rated for 75 watts. There is a reason why that slot is rated for 75 not 55watts.

FACT: the entire system has gone thru engineering scrutiny with CE/ UL listed approvals so that a fire for the most part wont start in a home\office with the rated parts listed. (IF) it didnt meet the approvals Dell would of derated the PCIE slot to a lower power out put to accommodate the engineering approvals needed for consumer use.

They are rated to have thermal durability and outputs matching that of gaming consoles which sometimes reach thermals exceeding 100C*.

Right now on my HP 800 G1 I have a i7 4790, 32GB ram, 3 ssd’s, and a RTX 4060 on a 180watt PSU and nothing has caught fire and some of the games I play I max out 100% CPU and GPU utilization.

I simply agreed with you about having an RX 6400 in your Optiplex because it's only 50w and a way you go.

It's not proven with Dell doctrine, like with recommended GPU's, or slot rating in an Owner's manual.  Dell did not validate 75w cards for their systems with 180w PSU's.  Some of those systems also have a CPU with turbo TDP.

Unsupported doesn't necessarily mean not working.  As long as 75w cards are working on a 180w PSU, all the power to ya'.

@bradthetechnut​  I've anecdotally ran GTX1650’s, RX560’s, RX 6400’s, GTX 1050/ti’s, and the most popular of all the GTX750ti.

The only real world way to know if its going to work is bu metering at the wall, and then taking a 12% conversion loss from AC to DC.

I speak from experience and being on this forum over 6.5 years.