Slow workspace performance

Hi, we've been having pretty bad performance issues with our AWS workspaces. We have about 25 instances in our account but regardless of the instance type (4 vCPU, 16GB included), we've observed performance has been bad. We initially assumed it was due to latency but we observed processing on the webbrowser or on word/excel is slow too.

Also we observed that sometimes the performance drops for all 25 instances at the same time.

How can i improve this? Are the workspaces somehow sharing resources?