Here is the difference in seconds with a 4090 and a 5090 and the settings I used.

SDXL
ZEP9 XL + 1280x1024 + 100 steps + 50 step face detailer + 50 step 2 x upscale + 50 step face detailer + film grain
5090 | 4090 | Diff
88.14 | 116.76 | 28.62
98.39 | 122.36 | 23.97
73.34 | 089.60 | 16.26
72.55 | 088.16 | 15.61
96.38 | 126.14 | 29.76
72.84 | 088.53 | 15.69
97.77 | 121.88 | 24.11
94.17 | 118.99 | 24.82
97.99 | 122.82 | 24.83
97.94 | 123.26 | 25.32
88.95 | 111.85 | 22.89 - averages

WAN 2.2
Q4 KS GUFF + 720x896 + lightx2v + lightning + sage attention + 8 steps + frame interpolation
5090 | 4090 | Diff
298.68 | 403.93 | 105.25
311.95 | 393.16 | 081.21
300.99 | 402.50 | 101.51
307.35 | 393.33 | 085.98
307.06 | 403.05 | 095.99
300.79 | 401.71 | 100.92
312.35 | 405.09 | 092.74
310.60 | 432.17 | 121.57
305.17 | 406.77 | 101.6
306.01 | 408.23 | 102.22
306.09 | 404.99 | 098.89 - averages