[seivadmas]

If you are writing Ruby you already decided you didn't care about speed.

Don't get me wrong, I think Ruby is a great language and I use it every day to get paid, but it is not a speed queen. Ruby's strengths lie in flexibility, fast iteration, readable code and permitting a functional style.

In most practical web applications the big bottlenecks will be either view rendering or database. Choosing to put any focus at all on performance of something like parallel vs serial assignment (unless you are doing something truly pathological) is a complete waste of time.

It will have no noticeable difference to the end user and distracts from the far more important job of making your code modular, extensible and readable.

If need your code to be fast and you are running Ruby, you already lost. Use Java or a compiled language instead.