the GameCube beats the PS2 in basically every aspect... except 1
CPU: 485mhz vs 295mhz
GPU: 13 GFLOPS vs 6.2 GFLOPS
Memory size: 43MB vs 36MB
although the GC memory was split into multiple pools with specific usecases, while the PS2's was only split between CPU and framebuffer basically.
it's also hard to compare due to the texture compression tech used by the Gamecube, which in practice multiplied the amount and size of textures you could use massively compared to the PS2... which had to use 4MB without any decent compression to increase the texture resolution and diversity.
that is easily seen in RE4 btw. where Capcom had to massively reduce texture quality and variety, as well as reducing the variety of the general assets like trees.
Memory Bandwidth: THIS is where the PS2 gets interesting. because you can't really give it a simple GB/s number. the PS2 is designed to just fill the screen with layers upon layers of textures.
with a pixel fillrate of 1.2 Gigapixels and a famebuffer bandwidth of 38GB/s, stuff like Metal Gear Solid 2 was almost impossible to do on other hardware at the time without severe adjustments to some of the effects, especially in the tanker mission.
for comparison the GC only had a pixel fillrate of 0.648 Gigapixels and a framebuffer bandwidth of 18GB/s
so this scene from MGS2 would have brought the GameCube to its knees without redoing all the rain effects and framebuffer effects:
the Xbox was barely able to bruteforce MGS2, and ran slightly worse still. so even the by far most powerful system of that gen couldn't keep up with the sheer amount of transparencies, screen effects and layers of texture thrown on screen at once.
...
but on the other hand, this scene from RE4 was literally impossible on PS2, without an insane amount of asset variety reduction, polygon reductions, texture quality reduction and texture variety reduction: