I just installed this GPU in my system today, upgrading from an ASUS RTX4090 Strix OC, with an EK Velocity 2 Water Block.
Both cards were measured on a Black Ice Nemesis GTR 420mm Radiator (just for the GPU) with 3 Be Quiet Silent Wings Pro 4 140mm PWM fans in pull configuration and a D5 Pump.
This are some benchmarks I ran, before and after.
Speedway
Watarcooled and Overclocked Asus RTX4090 Strix OC : 10920
Gigabyte Aorus RTX5090 Waterforce WB (Stock) : 14809
Steel Nomad
Watarcooled and Overclocked Asus RTX4090 Strix OC : 9975
Gigabyte Aorus RTX5090 Waterforce WB (Stock) : 14845
Port Royal
Watarcooled and Overclocked Asus RTX4090 Strix OC : 27836
Gigabyte Aorus RTX5090 Waterforce WB (Stock) : 38473
Time Spy Extreme
Watarcooled and Overclocked Asus RTX4090 Strix OC : 18453
Gigabyte Aorus RTX5090 Waterforce WB (Stock) : 22583
Fire Strike Ultra
Watarcooled and Overclocked Asus RTX4090 Strix OC : 26189
Gigabyte Aorus RTX5090 Waterforce WB (Stock) : 33402
DirectX Raytracing Feature Test
Watarcooled and Overclocked Asus RTX4090 Strix OC : 148.22 FPS
Gigabyte Aorus RTX5090 Waterforce WB (Stock) : 150.08 FPS
Mesh Shader Feature Test
Watarcooled and Overclocked Asus RTX4090 Strix OC : OFF 343.61 FPS, ON 1057.09 FPS, DIFF 207.6%
Gigabyte Aorus RTX5090 Waterforce WB (Stock) : OFF 377.65 FPS, ON 1380.02 FPS , DIFF 265.4%
PCI Express Feature Test (I don't think this test is working correctly and I have seen reports of the same online)
Watarcooled and Overclocked Asus RTX4090 Strix OC : 26.80 GB/s
Gigabyte Aorus RTX5090 Waterforce WB (Stock) : 105.27 GB/s