Hi Jim,
I'm a bit confused. AJAX (JavaScript) runs in a browser and just reads a file from the site (and shouldn't cause a 'CPU Overload').
Do you have a script that is invoked by VWS to push the current conditions to the website (via a GET-mode URL) like the WeatherFlash update script? Is that the script causing the issue?
It would help if you posted the (expurgated of user:pass info) code of the script(s) that seemed to be causing the issue, along with how they are invoked (by the website page or cron or VWS)
Best regards,
Ken