Question Slow overall PC performance and dismal benchmarks after installing an RTX 3070 ?

Dec 18, 2022
In trying to revive an old PC I purchased an rtx 3070 GPU upgrade. A while ago my old gtx970 had died. I reinstalled windows and got snappy general performance running off the integrated GPU. Once I installed rtx 3070, everything now seems incredibly slow.

Here is my UBM:

Motherboard- Z270 M5 Gaming
CPU- i7 7700K
GPU- rtx 3070
RAM- Corsair DDR4 Dominator 1x 16GB (downgraded from 2 sticks as one went bad)
OS- Windows 10 Pro
HD- Evo 500GB SSD
PSU- Thermaltake 1200W

Before installing rtx 3070 I installed Windows fresh, ran full updates, updated BIOS to latest and reset to factory defaults. Though shouldn't be needed I ran DDU after installing GPU and installed latest NVIDIA driver.

Clearly something is very wrong but not sure where to start in troubleshooting. Things run, just very slowly. Even internet speeds dropped, connected via ethernet, from ~350-500Mbs to 100-120Mbs.

Any help figuring out the issues may be would greatly appreciated.