As long as they’re all not running at the same time, what does it matter?
What do you mean by your site “overloading”?
by overloading I mean that the MySQL Connections shoot up to the limit of my hosting account’s ability.
I just looked at the pending cron tasks on one of my sites and I see only one update_plugins and one update_themes, so if you’re seeing multiples, there may be something wrong.

The number of mysql connections can be driven by traffic. How much traffic are you getting at the time the mysql problems occur?
they are definitely called “wp_update_pluginr”, I also have the three you list but only one instance of each.
It’s getting about 450 to 500 uniques a day – so not a huge amount.
With an “r”? Hmmm… doesn’t sound legit.
Try installing Wordfence and running a full scan of your system. If it’s clean, delete the cron jobs and see how long it takes for them to come back, if they come back. If so, then disable plugins one at a time until you find what’s creating them.
okay, i’ll try that. do you know of a plugin that allows you to delete more than one cron job at a time, the one I used to check the cron jobs only allows one at a time that it would take ages to do it that way.
thanks
wordfence didn’t find anything 🙁
just found a plugin that could delete all of them at once – there was 3000 of them!