Perfomance 9.1.9 vs 9.4.1

Dear,

I am comparing 9.1.9 and 9.4.1. I think that perfomance of 9.4.1 should be
better.
But I have an issue here.
I have installed both db on the same machine and I have 2 results,
where I see that for some reason 9.1.9 works faster - 118ms vs 452ms.
I checked the same sql query with EXPLAIN ANALYZE (with the same work_mem
=8MB and shared_buffers = 128MB).
Could you please help me what should I do to solve it?

1) 9.1.9
Limit (cost=6435.41..6435.41 rows=1 width=10) (actual
time=118.720..118.723 rows=25 loops=1)
-> Sort (cost=6435.41..6435.41 rows=1 width=10) (actual
time=118.719..118.720 rows=25 loops=1)
...
Total runtime: 118.921 ms
(48 rows)

2) 9.4.1
Limit (cost=507.65..507.66 rows=1 width=10) (actual time=452.124..452.127
rows=25 loops=1)
-> Sort (cost=507.65..507.66 rows=1 width=10) (actual
time=451.760..451.760 rows=25 loops=1)
...
Planning time: 3.406 ms
Execution time: 452.297 ms
(51 rows)

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Best regards, Alexander