Ruby Enterprise EditionEdit
"Ruby Enterprise Edition" (REE) is a fork of the official MRI implementation of Ruby that patches the memory allocator and garbage collector for better performance.
The actual performance improvement, if any, will vary according to the circumstances, but at least under the circumstances in which I tested it (see "Walrus compatibility and performance on different Ruby implementations") the gains were impressive.
The creators of REE have been criticized for producing a fork rather than submitting patches to improve the official implementation, particularly because of the hype-intensive marketing that they have used in promoting their fork.