IE and Chrome eat processor

Hello,

We have a RDS-Farm with 3 RDS-servers.

When users start Internet Explorer or Chrome, they start using a huge amount of processor percentage. Opening more tabs makes the servers go crazy.

We tried several things, but no results yet.

Some extra information: Running on ESXi 6.0, 48Gb per server, 2 processors per server. And: Running ESET File Security (Latest version)

Any clues?