inkpad lite - can't handle the math?

i got an inkpad lite not too long ago and i have to say i'm disappointed. i have a few books in epub format with a lot of mathematical symbols and the lite is amazingly slow doing whatever it does when i turn a page. it can take a minute or more for the page to display. the epub appears to be fine - it has no trouble opening and turning pages in ereader software on my pc and android.

any thoughts on what i might need to do to speed things up?

i tried koreader but it can't even display the proper symbols.