converting the attached ppt, which consists of 2 slides with 2 inserted png, takes about 4 s with jre7u51 (32 bit) on a 2.4 GHz Core i7 with 12 GiB of RAM.
Some experiments suggest that Aspose.Slides is quite fast (around 100-200 ms) for simple dcouments containing no images, whereas it becomes unacceptably slow when the ppt contains images (see attached example)
I have worked with the presentation file shared by you and have generated the PDF using Aspose.Slides for Java 8.4.0. The presentation shared is of 2MB owing to large images added in it. The rendering time and amount of memory consume is dependent on number of slides, shapes inside slides, size of presentation and amount of multimedia content available in slides.
The results shared by you are normal and are as expected. Please share, if I may help you further in this regard.
Yes, I understand that large images need more computing resources.
What is harder to understand is the 30-40 fold increase of computing time for a 2 slide presentation just because of 2 images that need no complex processing at all, just placing them on 2 pdf pages.
I guess there is room for improvements here.
Anyway, thanks for trying out.
Thanks for your efforts.