Isopropanol precipitation-best time and temperature-M

Hi, does anyone know what is the best temperature and time for Isoprop precipitation of DNA? I usually do at room temperature and centrifuge immediately. Can I improve this? And would it matter if I keep my samples on ice for 1-2 hours before centrifuging? I am courious to hear your opinion about this! Rybkasusa -rybkasusa-