The effect is very dependent on program structure and actual code running, but for a suitable application it's reasonable to expect anything from 5-15%, and som

The effect is very dependent on program structure and actual code running, but for a suitable application it's reasonable to expect anything from 5-15%, and sometimes much more (see e.g. Firefox reporting 18% here: https://glandium.org/blog/?p=3888 https://glandium.org/blog/?p=3888 )