We've had a number of performance issues with Umbraco 4.7.1.1.

First, we had to implement our own output caching (I can live with that) because Umbraco used far too much CPU and too slow.Tthe CPU was pushed to 100% with only 2-3 users on the site.

The second issue is bottlenecks in the code. we've analyized the code and found the culprit to be System.Web.HttpApplication.BeginRequest().

More specifically:
UrlRewritingNet.Web.UrlRewriteModule.OnAppPostRequestHandlerExecute()
umbraco.presentation.requestModule.context_PostRequestHandlerExecute()
We've seen response times of up to 3 minutes. Of course, this is unacceptable.

I'm wondering if we can increase performance by not using URL re-writing? We are Windows Server 2003/II6.

Also, this always happens when getting static resources. png, jpg, css & js files. Not sure if that means anything?

Finally, we are plagued with "Error loading MacoEngine script (file: _NameOfFile_.cshtml)". These are randomand can appear anytime a page has not been served from the output cache. The only thing I can say is we see it more often on our menu, which is at the top of the page, than other macros. We are using Razor script for all macros. These errors can happen anytime and are not related to server load.

I searched Google for the error and noticed that the Google bot has indexed a lot of sites with "Error loading MacoEngine script ", it appears in their site description. This is type of thing I must avoid at any/all cost. Is there any workaround or fix for this?

Any answers/help would be greatly appreciated.

Thanks!