2014 is very similar to 2013, and there have been no changes to the ability of Acad to take advantage of multiple processors. What 2013 could support, 2014 supports, and nothing more.
Performance is a somewhat different issue -- improvements were made, but whether you will see them depends on so many cofiguration variables that it's impossible to predict. The same tweaks that were used to speed up 2013 aply to 2014.
There's also the question of 'real' performance vs 'perceived' performance. While number crunching speed is one thing, the improvements in predictive UI could help you get things done faster, e.g. the enhanced command line and it's predictions about what you want to accomplish.