Unless I misread the post it's just comparing apples and oranges. If anything, the two benchmarks show that one piece of hardware (RAM) is orders of magnitude faster than the other one (SSDs). My previous comment was specifically about MySQL running on a machine where the whole dataset fits into memory.
Of course, I'm sure mapd is faster than mysql/postgres for some usecases. But the benchmark doesn't prove that in a fair comparison.
EDIT: Maybe I should add a disclaimer: I'm the founder of another open-source database product that could be considered a competitor to MapD.