[agib]

I have to agree with antirez here and call shenanigans. "WOW, MongoDB is almost a full 40% faster at incrementing than Redis" is simply a false statement. The correct conclusion for your post is "WOW, incrementing the same key 100k times with the mongo ruby gem in a very specific, single-threaded ruby application is 40% faster than incrementing one key 100k times with the redis ruby gem the in that same ruby application." If anyone makes a decision about a real world application based on your post, they will be making a huge mistake.