Unfortunately your statement thus far is too vague for us to do anything with. Can you provide us with the URL of the site you are measuring? What measurement tool are you using to determine the page load time?
There are also a number of things that can affect page loading time:
- How many posts/pages/events do you have on your site?
- Did you try this with the default Twenty Eleven or with another theme? It could be a conflict with your theme.
- Did you try this while turning off all the other plugins to see if there was some kind of conflict?
- Could be an issue at your hosting level
etc... There are a number of factors at stake here. I am also a bit concerned because even 2.3 seconds seems somewhat high for a baseline WordPress site without much in it, so there could be a conflict or other things impacting your site.
I don't mean to fully dismiss the issue either, as we don't want to be the plugin to slow your site down, but at the same, we've only gotten a small handful of similar support requests and in most cases the plugin alone wasn't the culprit; so please let us know if you have any specific findings so that we can help you fully troubleshoot this.
Let us know how we can be of further help,