Memory always above 90% and slow sychronization when cach option is on ?

Hello,

We are facing a problem with our MsExhange server 2013. We have a virtual solution on a physical server, We allocate to the Ms exchange 14G RAM. When the cache option is on, the server may take days to synchronize and see what others changed, so we decided to turn off this option.

1. Will this affect the performances of the server and the memory and CPU?

The server is always at 95% RAM. One more question, The minimum requirement resource for MsExchqnge is 8G RAM.

1. Will it be the same for a company having 100 employees and a company with 1000 employees. We are approximately150 is 14G enough for our server. Thanks for your suggestions.