1.5: moved hosting, and all is very slow for admin users

[chaim2003]

new VPS on a clean system. the forum is working OK for general (or logged-out) users, but it very slow for forum managers and admins.

I tried to debug it.
MySQL is OK - no slow queries, etc.
PHP itself is OK (phpinfo()).

I was found this trace for slow request:


XenForo_BbCode_TextWrapper::__toString 1.321 s
26,600
94.10%
XenForo_BbCode_Parser::render 1.321 s
26,600
94.10%
XenForo_BbCode_Formatter_Base::renderTree 1.321 s
26,600
94.10%
XenForo_BbCode_Formatter_Base::renderTreeElement 1.321 s
26,600
94.10%
XenForo_BbCode_Formatter_Base::renderSubTree 1.321 s
26,600
94.10%
XenForo_BbCode_Formatter_Base::renderTag 1.321 s
26,600
94.10%
XenForo_BbCode_Formatter_Base::renderValidTag 1.321 s
26,600
94.10%
XenForo_BbCode_Formatter_Base::renderTagQuote 1.321 s
26,600
94.09%
XenForo_Template_Public::render 1.322 s
26,600
94.09%
XenForo_Template_Abstract::render 1.322 s
26,600
94.09%
XenForo_Template_Abstract::_renderInternal


where to start?