Solvers available in BriefFiniteElement.NET

There are two solvers available in BriefFiniteElement.NET: 'Conjugate Gradient' and 'Cholesky' solver. you can set the model to use a specific solver with passing a parameter of SolverType type into Model.Solve method like this:

or
Note: if you do not provide SolverType for Model.Solve() method, Cholesky will be used by default.

Difference between Solvers in BriefFIniteElement.NET

I've found a pretty good information about difference of solvers in SolidWorks by Irfan Zardadkhan. I suggest you to see at least the last link (the video):

In BriefFiniteElement.NET there are two built it solvers available: and there is a very likely difference (regarding the error and accuracy) between these two solvers with solvers in SolidWorks.
In overal this is comparison table of two solvers:

Cholesky Solver (Direct Solver)
Conjugate Gradient Solver (Iterative)
Please have a look at Performance of BriefFiniteElement.NET to see more information about speed of solvers in action.