ESXi 6 - RHEL 7.3

Dear community,

I have performance problems with VMWare 6 and RHEL 7.3 on my fujitsu primergy rx350 s8.

I already updatet the server BIOS to the latest version. I reinstalled RHEL7.3 few times. But i always get CPu Soft lockups.
Also when i run the command : df -h, it can take up to a few minutes before is see the result of that command.
I have a subscription for RHEL7.3 and i also have a license for ESXi 6.0 so i can use all the 12 cores of the CPU.

The virtual machine is 1TB in size and it has some samba network mounts that are not used at the moment.
When i open phpmyadmin in the browser, then i can login, but i cannot view the tables of any database because all is going so slow.

Even when i tried this command : service mariadb start, then i sometimes get time out error.
Then i reboot the virtual machine and then i can get mariadb started.

Does anyone has the same problems?
And what can be the solution?