The component creates a realtime stream between clients visiting your site and remote server.
In some cases where the site has a lot of visits and concurrent users along as poor resources and bandwidth, you may experiment site slowness.
If this is the case, you can change setting for server load showed in the configuration of JRealtime Analytics. This will have the effect to reduce the server work and bandwidth usage.
If reducing server load you still experiment site slowness, consider to upgrade to a more powerful machine. Every extension to collect stats about every action on your site requires some kind of resources on server machine and bandwidth usage. Moreover JRealtime Analytics is built to be very lightweight and requires few resources to work, if you experiment this kind of issues probably you have a shared hosting with very poor performance or a site with hundreds of concurrent users.