There are some other interesting PostgreSQL FDW extensions targeting speed.

PGStrom uses the GPU: https://wiki.postgresql.org/wiki/PGStrom

PGOpenCL: http://wiki.postgresql.org/images/6/65/Pgopencl.pdf

PostgreSQL excels at heavy OLTP-type workloads; the MVCC architecture means that readers don't block writers, and writers don't block readers. But there is quite a lot of overhead for every row, and the query architecture is tuple-at-a-time, with lots of function calls. This means that OLAP workloads can be slow, compared to column store DBs like Vertica, MonetDB etc.