Some models take too long generating images

[DeSoreGD]

So I have these models: AAM XL(Anime mix), RealCartoon-Anime, and PD for Anime.
RealCartoon-Anime makes images literally in seconds, but the other 2 take like up to 5-15 minutes with the same parameters. Like quality is the same and images are not that different. I understand that they generate with different methods(ig), but it's just doesn't seem right.
Also some notices: When I use realcartoon it uses only 4 GB of RAM compared to other models where it uses all of my RAM. Also, realcartoon doesn't use shared GPU memory compared to other models.
My friend have the same issue with these models, all though he had no issues with models from 2022(ig), something wrong with new models? It's not only these models, ALMOST(some work fine) every model with size like 6 GB(5-15 minutes) seems to be very long in generating compared to 2 GB(several seconds)

[missionfloyd]

Also, realcartoon doesn't use shared GPU memory compared to other models.

It sounds like RealCartoon fits in your VRAM and the other two (which are each triple the size of RealCartoon) don't, so it has to use your system RAM, which isn't nearly as fast.

[DeSoreGD]

This doesn't happen with all larger sized models, so I'm guessing there is something else that is affecting the consumption of more VRAM(for example: animePastelDream_softBakedVae(7 GB), does generation within seconds). Also it's strange that 8 GB of VRAM is not enough for the model.