Thread abort, timeout with content query web part

I have a series of pages that each have 2 content query web parts and a custom web part.  One of the content query web parts is timing out intermittently.   I have column indexes configured on the sort column and filter columns.  It's set to query a single document library that has around 500 documents, which isn't a lot.  

We've upgraded the server to 16 GB of memory and it will still do this with only a few people hitting the site at the same time during off hours.   The custom web part on the page does an SPQuery on the same document library.

The query looks for specific content types using a taxonomy field that's been added in the page as a filter.  It also has 2 other filters configured.  With only 500 documents and 16 GB of memory there has to be  something else going on that I'm missing.

I've included the relevant ULS log entries.  Any thoughts?  

SharePoint Foundation         Web Parts                    89a1High    Error while executing web part: System.Threading.ThreadAbortException: Thread was being aborted.     at System.Threading.Monitor.Enter(Object obj)     at Microsoft.SharePoint.Publishing.CachedArea.GetCrossListQueryResults(SPSiteDataQuery query, SPWeb currentContext, Boolean onlyPopulateCache, Boolean useSpQueryOnList, Int32 lcid)     at Microsoft.SharePoint.Publishing.CrossListQueryCache.GetSiteDataResults(CachedArea cachedArea, SPWeb web, SPSiteDataQuery query, Boolean useSpQueryOnList)    at Microsoft.SharePoint.Publishing.CrossListQueryCache.GetSiteDataResults(CachedArea ca, Boolean useSpQueryOnList)     at Microsoft.SharePoint.Publishing.CrossListQueryCache.GetSiteDataResults(SPSite site, String webUrl, Boolean useSpQueryOnList)    at Microsoft.SharePoint.Publishing.WebControls.Conte...5ea9904d-edbd-41e6-a775-c3710e2cf58d
SharePoint Foundation         Web Parts                    89a1High    ...ntByQueryWebPart.IssueQuery()     at Microsoft.SharePoint.Publishing.WebControls.ContentByQueryWebPart.GetXPathNavigator(String viewPath)     at Microsoft.SharePoint.WebPartPages.DataFormWebPart.PrepareAndPerformTransform(Boolean bDeferExecuteTransform)5ea9904d-edbd-41e6-a775-c3710e2cf58d
SharePoint Foundation         Monitoring                    b4lyHigh    Leaving Monitored Scope (DataBinding DataFormWebPart (Product Information)). Execution Time=122332.6359914465ea9904d-edbd-41e6-a775-c3710e2cf58d
Web Content Management         Publishing                    7fovMedium  Caught a thread abort exception in TemplateRedirectionPage.ProcessRequest, the exception may be expected. stack trace=   at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)     at System.Web.UI.Page.ProcessRequest()     at System.Web.UI.Page.ProcessRequest(HttpContext context)     at Microsoft.SharePoint.Publishing.TemplateRedirectionPage.ProcessRequest(HttpContext context)5ea9904d-edbd-41e6-a775-c3710e2cf58d
SharePoint Foundation         Runtime                      tkauUnexpectedSystem.Web.HttpException: Request timed out. 5ea9904d-edbd-41e6-a775-c3710e2cf58d

---

Nate