I've been finding my laptop is "struggling" with some complex documents. For example, recently I was working on a moderately complicated presentation using PowerPoint 2010 (OS: Windows 7) and the application kept "hiccuping" over various display issue of the slides. I've a 120 GB SSD as my "C" drive and admittedly it is fairly "full". The behavior made me wonder if the relatively small amount of free space on SSD might explain the problem. I know that "cache" as such is not usually a part of SSD design. Would upgrading the SSD to a larger capacity be advisable for this sort of problem (if my assumption is correct)? Or is there another explanation/soulution?
Your description of your laptop does not adequately explain why PowerPoint would be having problems.
8GB of RAM should certainly be more than enough for a document of this size. You would be better off with your SSD having at least 20% free (according to Internet wisdom), and you'll want to make sure that TRIM is enabled. But 14%, while low, should not be causing these problems. Particularly as you say the file isn't even stored on your SSD.
If the file is stored on a standard rotational drive, you'll want to try defragging that, although this will likely make no difference. If it is stored on a network drive, you'll want to try copying it to your SSD. In fact, you may want to try that anyway. If it loads content from the Internet (e.g. an embedded youtube link or some such), you'll want to check your network connection. And it is always a good idea to ensure you have the latest drivers, especially for your video card.
You may also have other processes running and sucking up all your CPU time. Occasionally, antivirus software may cause this, too, although it is unlikely as I would expect the entire PowerPoint file to be loaded into memory (and thus scanned) before you start displaying the slides.
I'm sorry my answer is not more useful, but hopefully I've given you a couple of areas to take a look at.