How to measure postgresql performance

I have three different servers: VPS with one core cpu, desktop pc and i7 server. I run one sql request and got such execution time:

explain analyze select now();

VPS
 Result  (cost=0.00..0.01 rows=1 width=8) (actual time=0.083..0.084 rows=1 loops=1)
 Planning time: 0.024 - 0.450 ms
 Execution time: 0.021 - 0.295 ms

Desktop
 Result  (cost=0.00..0.01 rows=1 width=8) (actual time=0.003..0.003 rows=1 loops=1)
 Planning time: 0.014 ms
 Execution time: 0.038 ms

Server
"Result  (cost=0.00..0.01 rows=1 width=0) (actual time=0.001..0.001 rows=1 loops=1)"
"Planning time: 0.003 ms"
"Execution time: 0.005 ms"

Seems good for "quick test"