Unless you have very powerful hardware or virtual machines, anyone who has tried installing a full install of the new version of SharePoint 2013 Preview probably has run into problems with a bunch of noderunner.exe processes in your taskmanager just eating up practically all of your RAM and CPU making it very hard for you to do any development. I found this post by an MCM named Mark Priem  that indicates that this is most probably due to a memory leak in this beta/preview version of SharePoint 2013. I would assume this should be fixed in a cumulative update or hotfix quite soon.
Follow the steps below to limit the CPU and RAM impact on your system:
- In PowerShell, use the following to reduce the CPU impact the search service has on your test environment:
- Set-SPEnterpriseSearchService -PerformanceLevel Reduced
- <nodeRunnerSettings memoryLimitMegabytes=”0″ />