In partnership with IBM we researched PostgreSQL scalability on modern Power8 servers. 

That statement and the linked Russian blog white paper[1] makes it seem like a Power8 specific and Power8 is a "a massively multithreaded chip"[2]. I wonder how far off it would be to x86-64?

[1] https://habrahabr.ru/company/postgrespro/blog/270827/

[2] https://en.wikipedia.org/wiki/POWER8