Relative Performance HD
You should keep in mind that I used a more capable processor in the RTX 4070 and RX 7600, the AMD Ryzen 7 7800X3D, while all other cards were tested with an Intel i9-12900KF, which is the bottleneck for some strong cards, especially the RTX 4090, at HD resolution. The RX 7600 has a significant performance gain over the RX 6600 XT in the games I tried.
Relative Performance QHD
In QHD resolution, where the processor is not the bottleneck, for most graphics cards, the RX 7600 has a high difference from the aged RX 6600 XT.
Relative Performance UHD
This is not a 4K card, so this chart is only provided as a reference.