Some of the apps can scan/hash really hard does that effect others on my server?

Ocassionally I find some of the apps can hash or scan very very hard indeed.
Making access to the other web apps nearly impossible.
In situations like this would I be effecting other people on the same server?
As long as I'm partioned off to my own little limit on area I'm fine and not worried about it.
But if it is affecting other (containers?) it's a cause for worry, and not really looking to get
suspended because a app author didn't put in a way to renice ionice a hash/scan. =/