In comparison to Portage it is fast, but I wouldn't consider Portage a benchmark ;-) and if you compare Paludis with Apt/Yum/Pacman and the likes it is still very slow (e.g. comparing installing binary packages).
The comparison isn't completely fair, as Paludis has a much better dependency resolution algorithm (in terms of quality), but I think the main difference comes from the package format. Ebuilds/exheres are Bash scripts which need to be evaluated in order to obtain basic information like for example build- or run-time dependencies. So to find out which packages should be updated, Paludis has to evaluate a few thousand bash scripts while other package formats allow much quicker algorithms.
Cave is just a newer front-end for Paludis which improves the user experience a bit, but the Performance should be pretty much the same.
The comparison isn't completely fair, as Paludis has a much better dependency resolution algorithm (in terms of quality), but I think the main difference comes from the package format. Ebuilds/exheres are Bash scripts which need to be evaluated in order to obtain basic information like for example build- or run-time dependencies. So to find out which packages should be updated, Paludis has to evaluate a few thousand bash scripts while other package formats allow much quicker algorithms.
Cave is just a newer front-end for Paludis which improves the user experience a bit, but the Performance should be pretty much the same.