Specs needed to run SikuliX

--- the preciseness of image matching would be rather low.
That is wrong: the preciseness does not depend on processing power, since it is a defined number-crunching process, whose total processing time only depends on the size in pixels of the search-region (max the monitor size) and the size in pixels of the image searched for.

So the answer to your question is:
The minimum specs needed depend on what you expect to be the average turnaround time of a successful search operation.

For example on a system with a 2GHz+ processor and 4MB+ memory, the search time for an image of 200x200 pixels on a screen of about 1600x1200 should be less than 500 milli-seconds.

The smaller the search region for a given image, the faster the search.

So on a given system, that can run SikuliX, you have to make your own experience about the search performance.

A system capable to run SikuliX must have a valid Java 8 installation.

see:
http://sikulix-2014.readthedocs.io/en/latest/basicinfo.html#sikulix-how-does-it-find-images-on-the-screen

I am using Sikuli for UI testing since 2011. The lowest reasonable spec to have running Sikuli plus application under test for me is: 2 cores @2+GHz ,2GB Ram, and 1280x1024 display resolution. I am also taking care to control Sikuli scan rate when AUT will need more cpu power.