When processing is initiated, FineReader Engine loads all the necessary modules. Processing the second page takes less time because the modules are already loaded.
You can avoid the first-page delay by loading the necessary modules during FineReader Engine initialization using the Engine.LoadModule() method. Use

•  FREM_ImageSupport,
•  FREM_Export,
•  FREM_Recognizer,
•  FREM_RecognizerHP,
•  FREM_PDF,
•  FREM_FREngineProcessor,
•  FREM_ChineseTraditionalPatterns,
•  FREM_ChineseSimplifiedPatterns,
•  FREM_JapanesePatterns,
•  FREM_KoreanPatterns,
•  FREM_EuropeanPatterns

depending on which languages are used in your document images. We also recommend loading the Engine once and processing large batches, since the initialization times with this approach are negligible when compared to the total processing time.