I bought the 1650 SC Ultra last month to cheaply revitalize a 7-year-old rig with minimal bottleneck, and this thing is great for high-max settings in 1080p @60fps (in most games.) I was looking at an RX 580, and while the extra 4GB of VRAM sounded great, the extra 50W+ draw did not. Plus, the GTX is rocking GDDR6, which partially compensates for the slightly anemic memory capacity. This is also softened by the fact that I prefer scaling or SS over AA blurrovision (especially with FXAA and/or mild TAA.) Outside of that little caveat, the 1650 Super is roughly equal in gaming performance, although results tend to vary between the two across different titles. (I did a lot of research...lol)
I'm curious--which games did you test it on? (You mentioned a step down in performance.)
The only issues that I have had were fixed by avoiding the Adaptive setting in Power Management. I set it to Optimal Power for general use, and Prefer Max Performance for games. (Precision X1 reports the highest clock speeds ONLY when set to Max. Adaptive crashes under heavy load changes, and Optimal is calm and cool--e.g. it behaves as it should. (Game-Ready driver v.456.71))