PhoenixFireX76

Did you plug in an external power cord in the side? My RX 480 had a second power cord to add to the power already drawn from the PCI-E port (which stumped me for about 30 mins) and considering the RX 570 is a superseded the RX 480, I would expect the same. (Nevermind I see you plugged it in the photo) Did you get the GPU from Amazon? Was it a used card? Did you get it from a reputable seller? Since you already tested it on an already working computer, it could be the PCI-E connector on the GPU's side and you just got unlucky both times. Another option could be that motherboard or PSU can't support the Graphics Card, or that the RX 570 was overclocked (If it's used) and that is preventing it from posting. Try using the integrated graphics and see if device manager recognizes it.

The GTX 950m doesn't really work for older games either but, I mean, you could play something like Minecraft Win 10 with 60 if you really wanted to get some fps around there. If it's just stuttering, I suggest you put the fps limiter on 30, as some people are usually ok with that, so 43 fps is actually not so bad. The 4GB of RAM could also bottleneck your CPU, but who am I to say anything?