Hi, Thank-you for your response.
Unfortunately, I am already familiar with this information and had already taken these measures before making my last post.
My Windows power settings are set to High Performance, I have also checked the individual advanced settings to ensure nothing was set incorrectly.
I have checked my BIOS settings and disabled parking on all cores.
I have checked the Task Manager for any process CPU or Memory usage during this issue.
I would not really class this issue (at least the issue I am having) as lagging though, rather a constant drop; Where my frame rate was once >100fps constantly, it is now <20 constantly.
Regardless of settings mentioned earlier.
I will also note that I have tried a few more things since:
Remove, reseat graphics card, check PCI-e power connectors to GPU.
Reinstall Windows 10 and install fresh NVidia drivers.
One very important note is that, one in every 20-30 launches, the game will work PERFECTLY, and as long as it is running, it works great, >100FPS!!
Just want to give you the most information I can, thanks again for the help.