increase RAM usage

Hi

I am trying to work with a model that has very high polycount, like 500K. Blender crashes when i try to do operations like Smart UV Unwrap ore split by Material. Would it help to increase Blenders usage of RAM and how would i adjust that?

greetings

Blender automatically uses all the RAM that it can get, unless it is limited by the used OS (32 bit?).
How much RAM do you have in the system and what OS do you use?