Without knowing more about your computer, it is hard to say if Everquest II will run on it or not. That being said, if everything else meets or exceeds the minimum requirements and you are only worried about the apparent loss of 6MB of RAM, from your total cache, then it should run. Regardless, you need to upgrade your RAM to at least 1024MB.
You will have a much more enjoyable playing experience with more RAM, and it is fairly cheap to upgrade. If you read the other posts on this board, most people say their lag pretty much disappears, with the exception of city zones, after upgrading to 1024MB and many of those already with 1024MB are talking about upgrading further.
In short, upgrade. You won't regret it.
Kallirye