Disk Caching or Memory Caching?

As the title says... I'm quite confused as to how the two methods usually utilized by shadowing products work. Does disk caching write system changes to the cache only when there is a change OR does this method clone all the files from the hard disk to the cache thereby effectively doubling the needed space. As for memory caching, how much memory do programs (well perhaps just a program since I only know of only one which shadows into memory) need to cache changes?



On a side note, can someone enlighten me on which of the 2 methods would be better suited for a pc which I mostly use for gaming and with files only changing during game patches. (I'm leaning towards disk caching since mmorpgs need much memory but that's from my nubie point of view would gladly hear out thoughts from experts)

 

Memory caching is faster and there for probably preferable when it comes to gaming. But there are variables to consider as well. Amount and speed of the memory being two of them.

I will have to leave the first part of your question up to those who use the type of product(s) you you mention.