GTX 1080 running at 139 MHz. Works but not properly

[Namegoese(here)]

I have an HP Z620 that I recently acquired. Installed an Asus Turbo GTX 1080 that I got from a family member. System posts, windows works without problem, graphics card detected. I can run games, PUBG low 30 fps, Halo Infinite Low 30 FPS. Something was wrong. In GPU Z it shows the graphics card does not receive PCIE 8 pin power. I had to use a 6 pin to 8 pin adapter but the power supply in the machine supplies more than the normal spec for 6 pin. From factory it includes the adapters but the person who gave me the machine didn't have them anymore. GPU clock speed is also 139 mhz, can't change it in afterburner or the Asus specific tool. GPU Z shows that there is a voltage just no watts is being shown.

 

Troubleshooting attempted:

Motherboard bios

GPU drivers

Clean install of windows

GPU Vbios

Changing cables

Changing adapters

Changing bios slot speed settings

Changing windows power control settings 

Changing Nvidia controller power settings 

Changing pci e slot

Afterburner settings

Asus specific tuning tool settings, set power usage to 100% and no change 

 

I am going to remove the power supply and test it with a multimeter tonight.

 

Im now under the assumption that the card is dead. I purchased a new dual 6 pin to single 8 pin adapter which is sketchy but I'm willing to try it, I've seen others with this machine making that work. 

 

Anything else I may be able to try without that adapter? I've done lots of computer troubleshooting over the years, but very little hardware related, mostly software issues. Mainly a Mac guy and deal with large scale networking of AV equipment. 

 

Windows 10 pro

Newest bios from HP

Intel Xeon e5 1660 V1

48 GB of ram 1600 MHz 4 8 gb 4 4 gb

Asus Turbo GTX 1080

800 watt 90% efficient power supply