Question: Can you actually take an image of your system drive on a mechanical hard drive and put it on an nvme drive?

Thanks in advance for the help

Answer:

Shouldnt it be able to give me at least 500-600MBps? Thats still much faster than my mechanical drives

Which is exactly what a SATA III SSD drive will do.

In that system, a 970 (or even worse a 980), will give zero performance difference over a Samsung 860 EVO or Crucial MX500. SATA III SSD.
And those WILL work 100%.