I/O Rate/Second is more Important

While the system hit ratio improvements tapered off after 7000 buffers, we can see that the I/O rate shows large reductions at 7000, 11000, and 15000. Improvement does continue after that, however the payback is less for the same additional memory size increments. So – going up to 15000 buffers (36 Meg additional) saves 47 I/Os/Sec. If large amounts of memory are available, increasing to 31000 buffers (another 48 Meg) saves 11 more I/Os/Sec….. For a total reduction of 58 I/Os/Sec.

This is an I/O rate reduction of 44%+.