Acrobat X pro - Reduce File Size

Having recently  (I know, I know ) moved from CS5 TO CS6, and their corresponding versions of acrobat - here is what I notice.

If I created a reduced size ( compressed ) PDF in what I guess was Acrobat 9 - and these are always just files of jpeg photos, etc - the biggest difference was that the reduced size version would load slower.  It was pretty consistent in its % of reduction, a 10 Mb file would become 4 Mb, but I was never really able to discern a qualitative difference in the images. What I noticed, as I said, is that they would load slower. If you tried to flip or quick too quickly, the next page would load in chunky blocks.

If you went through the pages at a reasonable rate - only advancing every 2 or three seconds say - everything was fine.

In Acrobat 10 Pro however ( this running on Windows 10 ), the reduced file size PDF's look like crap. All manner of visible hard lines and clunky lego-style stuff going on.  The pages load quickly though - but who cares cause they look like $#!t.

Does anyone know a way or technique to do what the previous version of Acrobat seemed to do, reduce the size by means of compromising the speed at which the pages loaded - without sacrificing the quality of the result ?

Or must I transfer everything to my old computer and use Acrobat 9 whenever I have to compress a PDF ?

Thanks for any help or guidance,

Sterne