You may have an R setup that is not using hardware resources in an efficient way.
Linear algebra libraries such as OpenBLAS and Intel MKL can compute matrix/vector operations with all available processing power to significantly reduce computation times.
Use apt-get instead of compiling sources
If you prefer to use
apt-get there is an option. Intel MKL is hardware specific while OpenBLAS boosts operations both for Intel and AMD
To install R linked to Intel MKL, Dirk Eddelbuettel’s blog provides detailed instructions.
To install R linked to OpenBLAS you only need this:
sudo apt-get update sudo apt-get install libopenblas-base r-base
I’ll stick to R 3.4.2 that is what I use at work.