Bytea poor performance

Hello,

I am trying to select form table with bytea field. And queries runs very
slow.
My table:
CREATE TABLE files (file bytea, nr serial NOT NULL) WITH OIDS;

Query:
select * from files where nr > 1450

(I have total 1500 records in it, every holds picture of 23kB size)
Query runs very long:
Total query runtime: 23625 ms.
Data retrieval runtime: 266 ms.
50 rows retrieved.

explain:
Index Scan using pk on files (cost=0.00..3.67 rows=50 width=36)
Index Cond: (nr > 1450)

Is it possible to do something with it? or it is normal? Our server is
fast, and all other tables work fine..

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