Very interesting chess engine called Murka 3. It comes with source code.
It is single threaded but on a single thread I get 3.2 MNPS with the 64 bit version in the distribution and 3.5 MNPS with a simple PGO compile.
I guess that Jim Ablett could do a lot better with his compile.
GCC won't compile it because it uses lots of Windows specific stuff. I think probably you would need MS VC++ to build it (unless you fix the OS and compiler specific issues).
Small source code base, and gets time to ply quite well for a single thread engine.
Worthy of examination, for sure.
I found it here:
http://www.sdchess.ru/download_engines.htm
