I couldn't go to bed without sharing this tip with any Open Office user.
The original(and better) info is here:
To sum up:
Start Open Office and click on "Tools -> Options". This should open the configuration. Click on "Memory" in the left menu and change the following settings:
# Number of Steps: 30
# Use for Open Office: 128
# Memory per Object: 20
# Number of Objects: 20
Click on "Java" in the left menu afterwards and uncheck "Use a Java Runtime Environment". Click "OK" and restart Open Office to see how fast it is now.