Stimulsoft ships two rendering engines. Preparing the same report on each lets you compare their memory footprint and behaviour.

Select the engine per report. Set EngineVersion before compiling:
report1.Load(stream);
report1.EngineVersion = StiEngineVersion.EngineV1;
report1.Compile();

report2.Load(stream);
report2.EngineVersion = StiEngineVersion.EngineV2;
report2.Compile();

How it works. Both reports use the identical template; only the engine differs, so any difference in memory or speed comes purely from the rendering strategy.