I've been playing minecraft and it constantly crashes (pretty much like 3 times in less than ten minutes)

So, I'm playing Minecraft on a server (Mineplex) and it constantly crashed 3 times in the same ten minutes I've been playing. Minecraft has crashed before an it wasn't so constant and often. This only happens on my NEW computer, which is the one I am using. I have the new updates and the latest java too.
What I expected to happen was...:
Describe what you thought should happen here
I expected Minecraft to not crash
What actually happened was...:
Describe what happened here
What actually happened was Minecraft kept on crashing constantly
Steps to Reproduce:
1. Doing just about anything apparently...