Download large file without buffering - asp.net-mvc

Question

I am getting an OutOfMemoryException attempting to download a large file from an MVC controller. I want to reduce demand on server memory, so how can I download a file without first buffering its entire contents?
My code is:
var cd = new System.Net.Mime.ContentDisposition
{
FileName = filename,
Inline = false
};
Response.AppendHeader("Content-Disposition", cd.ToString());
var stream = new MemoryStream();
ExportService service = new ExportService(_mapper, Repository);
service.ExportVersion(view.ExportType, version, products, regions,
indicators, periods, stream);
stream.Position = 0;
return File(stream, "text/plain");
I would like the content to be streamed to the browser as I am creating it. To try to acheive that, I passed Response.OutputStream to the service and wrote to that instead of to the MemoryStream. However, that creates the same OutOfMemoryException, since by default, ASP.NET buffers all content before sending it to the browser. Even if I set Response.BufferOutput = false (and return an EmptyResult) I still get an OutOfMemoryException.
Response.BufferOutput = false;
ExportService service = new ExportService(_mapper, Repository);
service.ExportVersion(view.ExportType, version, products, regions,
indicators, periods, Response.OutputStream);
return new EmptyResult();
Update
I am confident that this problem is due to hitting the limit of available memory since the code works on one machine, but not on another. Furthermore, on the machine with the more restricted memory, the strack trace shows the error occurs at variable locations in the code, depending on the content being downloaded. Here is a sample stack trace which shows the exception occurring while allocating memory to a List object:
[OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.]
System.Collections.Generic.List`1.set_Capacity(Int32 value) +62
System.Collections.Generic.List`1.EnsureCapacity(Int32 min) +43
System.Collections.Generic.List`1.Add(T item) +51
MyApp.Mapping.DocumentVersionEntityConverter.LoadMultiVariableData(DocumentVersion version, MultiVariableQuestionView view) in c:\svn\Client Applications\MyApp\Web\Config\Mapping\DocumentVersionEntityConverter.cs:207
MyApp.Mapping.DocumentVersionEntityConverter.SetResponses(DocumentVersion version, List`1 questions, DataFilters filters) in c:\svn\Client Applications\MyApp\Web\Config\Mapping\DocumentVersionEntityConverter.cs:112
MyApp.Mapping.DocumentVersionEntityConverter.ScanSection(DocumentVersion version, SectionView section, DataFilters filters) in c:\svn\Client Applications\MyApp\Web\Config\Mapping\DocumentVersionEntityConverter.cs:79
MyApp.Mapping.DocumentVersionEntityConverter.Convert(ResolutionContext context) in c:\svn\Client Applications\MyApp\Web\Config\Mapping\DocumentVersionEntityConverter.cs:63
AutoMapper.DeferredInstantiatedConverter`2.Convert(ResolutionContext context) +57
AutoMapper.<>c__DisplayClass15.<ConvertUsing>b__14(ResolutionContext context) +10
AutoMapper.Mappers.CustomMapperStrategy.Map(ResolutionContext context, IMappingEngineRunner mapper) +13
AutoMapper.Mappers.TypeMapMapper.Map(ResolutionContext context, IMappingEngineRunner mapper) +130
AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) +355