Are your Orchard CMS projections and queries running slow?
Your answer: Eager Fetch Filter
"Eager fetch filter for Projections enables you to specify what part records to load up front to avoid "select n+1" problems." ...introduced by the Orchard CMS steering committee on 10/08/2013
As far as I know this made it into the Orchard CMS 1.7.2+ versions and the 1.8+ versions (if you are upgrading make sure you go all the way to 1.8.1...don't stop at 1.8.0).