Why is LRU better than FIFO?

Question

Why is Least Recently Used better than FIFO in relation to page files?

Answer 1

If you mean in terms of offloading memory pages to disk - if your process is frequently accessing a page, you really don't want it to be paged to disk, even if it was the very first one you accessed. On the other hand, if you haven't accessed a memory page for several days, it's unlikely that you'll do so in the near future.

If that's not what you mean, please edit your question to give more details.