The AMD RX 9060 XT 16 GB wins in 11 out of 15 comparable specs, with 3 ties. Its biggest advantage is FP32 Performance (142% better).
RX 6600 XT wins in 1 spec (Base Clock: 16% better).
Recommendation
Choose RX 9060 XT 16 GB if you want the best overall performance — especially fp32 performance.
Choose RX 6600 XT if base clock matters more to you.
