Issue with Cache timeout

I run a very large site with over 200k posts and have dozens of new posts very day, the issue with the plugin is that I set the cache timeout at 1800, which means it will recycle the expired files every half hours. However, so many exsiting post and I post very frequently, every recycle cause my CPU to spike and I had to wait a few minuite for it to cool down before posting again. I want to know if I set it to like 12 hours for each recycle instead of 30mins, what would be the downside for this move? Will each recycle crash my server?