Why this script?
My script is modified from 
Their scripts build steem using standard Makefile genarated by CMake, which cannot take advantage of mordern hardware. The building process is very slow. On my Dual-Xeon server it takes about half an hour. Simply using make -j 8 doesn't speed up building, unfortunately. So I modify their scripts to build steem with Ninja-build, a blazing fast building tool.
Using this script
Download and run the latest script:
https://github.com/adoal/install-steemd-fast/raw/master/install-steemd.sh
chmod +x install-steemd.sh
./install-steemd.sh
You can, of course, run it manually by following the steps inside this script.
How it works
Source code of Steem is written in C, with boost. Compiling C code with template heavily used is a time consuming job. Traditional Makefile is built one-by-one serially. There is a -j directive to run several make task, but it depends.
Since the building system of Steem is CMake, which is in fact a building-script generator instead of a bottom layer building system, we can try other backends, not the default Makefile. Ninja-build is a modern one. It defaults to run equivalent number of tasks to that of CPU cores.
As a compare, on a HP Proliant BL460c G7 server, with Dual 6-core Xeon 5650 2.67GHz and 48GiB memory, standard Makefile takes exactly half an hour, while Ninja-build takes 7.5 minutes. The accerating ratio is 4 instead of 12, because there are dependencies between subtasks which keep the building process from fully parallelized. But 1/4 time is amazing fast too :)