Is there something else to consider that may be causing the issue? For example the file seems to run much faster on my home computer (Win7, SU 2015 Pro) versus my work computer stated above.
File Format: By default, Binary is selected from the drop-down list.This option is helpful if you want to model several parts that fit together in one SketchUp model file, but export each part to a separate 3D-printable STL file.
Export Only Current Selection: When you select this checkbox, SketchUp exports only the selected geometry to the STL file.The STL Export Options dialog box enables you to choose a few options for how SketchUp renders your exported file: SketchUp exports your model to the STL format and saves the file in the location you specified. Back in the Export Model dialog box, click Export.(See the following list for details about each option.) Click OK when you’re done. (Optional) Click the Options button, and in the STL Export Options dialog box, select your desired options for the exported STL file.From the Format drop-down list, select STereolithography File (.stl).From the Save As Type drop-down list, select STereolithography File (.stl).