Oh yeah, it'd be capable of all those games. It'd probably be able to run most of them on high. I don't know what Dwarf Fortress is, though.
Basically, Dwarf Fortress uses all the CPU it is provided with to help the game run with higher FPS, So high CPU so I can run the wiki and have a good framerate at 70 Population would be nice.
Something possibly like or better than:Operating System: Requires Windows NT 4.0, Windows 98, or newer (If on a non-Windows OS, see System requirements#Other Operating Systems for information on how to install Dwarf Fortress)
Disk Space: ~100MB. The game itself takes only about 20MB, but savegames and screenshots (if you take them) use considerable amounts of disk space. It is possible to use over a gigabyte of disk space with Dwarf Fortress.
RAM: 256MB. The game uses 150+ MB memory while running (more if you select a local grid larger than 6x6). The more creatures, objects, and explored space on your map, the more memory you will need. Most of this can be kept in virtual memory (page file), but be sure to have at least 500MB total (physical + virtual) memory available. World generation requires 400MB at its peak.
CPU: Dwarf Fortress is able to use as much CPU power as you can provide it with. While a Pentium II at 500Mhz is initially sufficient, your frame-rate will substantially decrease as your population increases, among other factors. Keep in mind that Dwarf Fortress will only run on one CPU at a time. There doesn't appear to be any indication that Dwarf Fortress will support multi-threading in the near future.
The larger your map and the more units on it, the harder your computer will need to work. The speed of the simulation depends on the size of the map, the number of entities (dwarves, pets, etc.), the number of levels (mountainous maps have more depth levels), the number of objects and other factors. Modern computers should be able to run 3x3 maps with medium-sized fortresses at 80-100 FPS. Particularly fast processors may be able to handle much larger maps at the same speed.