[vivek@matrix] ~ $ time npm config get prefix
/home/vivek/.nvm/versions/node/v6.7.0
npm config get prefix 1.44s user 0.49s system 5% cpu 33.127 total
[vivek@matrix] ~ $ time npm config get prefix
/home/vivek/.nvm/versions/node/v6.7.0
npm config get prefix 0.31s user 0.02s system 106% cpu 0.308 total
[vivek@matrix] ~ $ time npm -g prefix
/home/vivek/.nvm/versions/node/v6.7.0
npm -g prefix 1.30s user 0.29s system 22% cpu 7.023 total
[vivek@matrix] ~ $ time npm -g prefix
/home/vivek/.nvm/versions/node/v6.7.0
npm -g prefix 0.31s user 0.02s system 105% cpu 0.306 total