Never Increase vertices in cylinder more than 100000
If you increase your blender would hang and then disk load would be 100% and even if you have a 512 SSD laptop it would make you shut down and you will lose all your unsaved work.
Now you may ask why would anyone do this?
Well, you are right but some people use to test like me(especially beginners) so they just think it would make it perfect cylinder but ultimately realized what a big mistake they had done.
I cant add the snapshot of disk load 100%as i could not do anything but just shut down my PC.
Warning Never try this.
Thanks.