The fastest, most efficient file manager in Linux is the set of GNU tools including ls, cp, and so on. But if you want a graphical user interface, you pay a cost in overhead. Considering how important file management is, and how easy it is to screw it up, a good GUI is probably worth the overhead. For Gnome users, Nautilus does the job well, with all the bells and whistles. KDE has its own version and I’m sure everybody who uses it loves it.
But, new fangled file managers also tend to get bloated with features over time. I’ve been thinking of creating a couple of my own file managers that are simpler to use and do the job more quickly. There are a number of text-based file managers as well, that run in a semi-graphical way in a terminal. For one thing I do quite a bit of, I would like one file manager that always opens on the same exact directory, and I do not need the ability to do anything other than open a file in that directory in a certain program, sort by date or name, change the filename, and drag/copy the file to another location when I’m done with it. Always the same location. Seems like that could be done in a simple Python script. Some day I’ll get that done.
In the mean time, there is an interesting altnernative file manager that was designed for the Xfce desktop but that works great on Gnome. It is leaner, meaner, possibly more customizable than Nautilus, and will take you a few seconds to install from your package manager. It is called Thunar. Here is the web site for Thunar. Give it a try, it can’t really hurt.*
*(and if it does that’s your prolbem not mine, just so you know….)