Whole problem of compatibility SN and mChat is in loading necessary JS code.
mChat adds to site your jQery core bottom of HEAD section.
SN adds to site your jQuery core above mChat adds. Above mChat adds are also the scripts for SN. When is again jQuery core loaded using mChat, are the scripts for SN blocked.
Yeah I am aware of this and fixed it as per what previous users reported here as previously reported, didn't use mChat's jquery, only SN's. They were both fully functional with it. That isn't my problem, unless using only SN's jquery causes mChat to cause server overload.
The overloading (not bandwidth, not sure exactly what it is, seems like CPU,) was now fixed by removing the IM from the mChat custom page.
I want to try to use only the latest jquery everywhere, see if that won't fix the issue. But I can't find where SN loads it's jquery-1.4.4.min.js? It's not in im.html? -- EDIT: found it in overall_header_hooks and tried it, didn't fix the problem.