The SCF Macs use the fast, threaded BLAS from Apple's Accelerate framework. To enable this on your own Mac, you can do the following to replace R's default BLAS with the Accelerate version. You'll need administrative privileges.
cd /Library/Frameworks/R.framework/Versions/Current/Resources/lib mv libRblas.dylib libRblas.dylib.bak ln -s /System/Library/Frameworks/Accelerate.framework/Versions/Current/Frameworks/vecLib.framework/Versions/Current/libBLAS.dylib libRblas.dylib
To change the number of threads used, follow the instructions above for Linux but use VECLIB_MAXIMUM_THREADS rather than OMP_NUM_THREADS.
To enable openBLAS with R on your own Windows machine, see here.