wp-cron.php overloading my server

My host, Servint, is telling me that my my very large dedicated server is being brought to a slow crawl at least twice every day by scheduled cron jobs triggered in the wp-cron.php. They claim that the wp-cron.php is running a script on all of my sites at once, at the same times, and since I have hundreds of WP sites on that server, they say it maxes out my RAM and CPU usage loads during these hours.

I don’t know why this wp-cron.php script would run at the same moment on hundreds of sites, instead of being naturally staggered, but if that is indeed the culprit, they’re saying I either need to find a line in the code that allows me to stagger the times manually, or spend hundreds more a month for an even bigger dedicated server with more RAM.

Any wisdom & help with this would be greatly appreciated, thanks

RE