Question: I am using AUtomapper which I am very impressed with however, I have a complex object with many nested collections. I'm using Telerik OpenAccess and it returns the 1400 records fast but when I pass it to Automapper and it slows to a ridiculous crawl. Here is my code for reference:

```
        List<DAL.Event> query = httpContext.Events.Where(e => e.Inactive != true && e.Event_Locations != null).ToList();
        Mapper.CreateMap<DAL.Event, EventDTO>();
        Mapper.CreateMap<DAL.Event_Association, EventAssociationDTO>();
        Mapper.CreateMap<DAL.Event_ExecutingUnit, EventExecutingUnitDTO>();
        Mapper.CreateMap<DAL.Event_Funding, EventFundingDTO>();
        Mapper.CreateMap<DAL.Event_Location, EventLocationDTO>();
        Mapper.CreateMap<DAL.Event_Objective, EventObjectiveDTO>();
        Mapper.CreateMap<DAL.Event_OSR, EventOSRDTO>();
        Mapper.CreateMap<DAL.Event_PaxBreakDown, EventPAXBreakDownDTO>();
        Mapper.CreateMap<DAL.Event_RegionalConsideration, EventRegionalConsiderationDTO>();
        Mapper.CreateMap<DAL.Event_ReviewStatus, EventReviewStatusDTO>();
        Mapper.CreateMap<DAL.Event_SPCalendarClone, EventSPCalendarClonesDTO>();
        Mapper.CreateMap<DAL.Event_Task, EventTasksDTO>();
        Mapper.CreateMap<DAL.Event_TSO, EventTSOsDTO>();
        Mapper.AssertConfigurationIsValid();
        Mapper.AllowNullDestinationValues = true;

        IList<EventDTO> result = Mapper.Map<List<DAL.Event>, List<EventDTO>>(query);
        return result;

```

HELP!

Answer: 
I benchmarked automapper. A single core of a 2.0GHz Xeon is able to handle 85,000 maps per second, on a small object (3 properties). It was 60 times slower than manually copying the properties. If you'd like, I can benchmark other values for you.
For those coming to this later, AutoMapper 5.x release made significant performance improvements, where mapping speed is only slightly slower than hand mapping (1M items):

* Native: 0.19s
* AutoMapper: 0.49s
* AutoMapper 4.2.1: 29s