greenmedic88 on 16 September 2010
I want to say that the PS3 reserves roughly 10% of the HDD capacity for cache, system data, security, etc.
A 320GB HDD was about 298GB formatted with OS installation. If I remember correctly a 500GB HDD was less than 460GB formatted. A 60GB HDD was about 55GB formatted and a 40GB HDD was 36GB if memory serves me correctly.
So a 120GB HDD would be about 108GB formatted, maybe a bit less.
You can check the Game Data Utility to check the HDD allocation for every game that uses installation space.
