The algorithm used in QuickField solver does not require the whole data of the problem to fit into memory of your computer. The solver can effectively handle linear algebraic systems with matrices several times bigger than the amount of available physical memory. Data that don't fit into memory are stored on the hard disk. The size of the problem you can solve on your computer is only limited by the amount of free disk space. Memory consumption is very low compared to other FEA packages, only about 2.7 MB per 10'000 degrees of freedom.
Although size of the problem is not limited by the amount of available memory, having additional memory may improve performance. It is obvious that the performance is the best when all the data can be stored in memory and relatively slow disk access is not used during solution.