strange issue. im taking my gtx 950 from old PC and putting in the dell alienware R9, but get no display.
now the odd thing is, at one point i did get display but not anymore.
THe computer doesnt seem to fully power on as the led on the keoyboard remain solid, cant turn them on/off.
i have reasearch and researched but cant find anything. It seems its not realted to the whoel UEFi bios stuff as my PC is brand new, and is running uefi.
i even disabled secure boot. Still nothing.
there doesnt seem to be a uefi bios update or anything for the gtx950, the card is like 3 years old so it must be uefi compatible.
 
If i stick in the gtx1650 in the other pci slot, it seems to boot normally "most of the time" and at point i get display from both video card!!
its like it cant decide which card to use, race condition?
the dell power supply does have the 6pin poiwer connector which i plug into the card...
 
im lost, not even easy to explain whats the issue...please help..

no one?

Did you uninstall restart system than reinstall the NVIDIA driver? Edit: After that I would yet again restart system so the driver runs smoothly.

The issue is at power on, bios level. So drivers have no role at this point. But yes i have done that in any case.

I am going to assume the GTX 1650 was an Dell OEM card but what about the GTX 950?

If the GTX 950 card .. does not show up in BIOS - it seems to be a MB or BIOS setting issue
 
1) Record your BIOS settings - cell phone camera
 
2) Try different PCIe slot ... check PCIe settings in BIOS
 
3) You have an iGPU ?  Is it connected to a monitor Or turned off ?
 
4) Load Default settings & then on reboot, Now Clear CMOS, reboot & reload default BIOS, reboot again & edit BIOS for your HD
 
 
MB & BIOS version ?
 
OS details ?
 
 

Here are the BIOS versions for your PC, from initial release (1.0.2) to the latest (1.0.7)..Update if needed, if not, try an older version..Make sure CSM (Compatibilty Support Module, that provides legacy BIOS compatibility by emulating a BIOS environment, allowing legacy operating systems and some option ROMs that do not support UEFI to still be used.) is enabled.

Update your bios to the latest version if you're not already running the latest bios.

Yes the 1650 is the oem card. It also works fine multiple PCs. My GTX is retail, also works in mulitple pcs fine, excepp in my Dell R9. 
The computer is on the latest bios from Jan 2020. one thing to note is that the Pc has the new UEFI ONLY BIOS. It has no legacy/CSM bios option. i suspect thats where the issue is from. Perhaps the GTX950 cannot work in a UEFI ONLY PC.

700 series and up support uefi.