On the other hand, it has been shown that under certain circumstances adding more
memory can, in rare cases, actually cause an increase in page interrupts when using a
FIFO policy. As noted before, it is called the FIFO anomaly. But although it is an
unusual occurrence, the fact that it exists coupled with the fact that pages are removed
regardless of their activity (as was the case in Figure 3.8) has removed FIFO from the
most favored policy position it held in some cases.