pg_dump and psql disagree on numerical precision (powerpc)

I didn't believe it at first:

create table test ( x double precision);

insert into test values (0.3);

test=# select * from test;
x
-----
0.3

--
-- Data for TOC entry 3 (OID 53248)
-- Name: test; Type: TABLE DATA; Schema: public; Owner: christof
--
COPY test (x) FROM stdin;
0.29999999999999999
\.

psql --version
psql (PostgreSQL) 7.4RC1

\set
VERSION = 'PostgreSQL 7.4RC1 on powerpc-unknown-linux-gnu, compiled by
GCC powerpc-linux-gcc (GCC) 3.3.2 (Debian)'

pg_dump --version
pg_dump (PostgreSQL) 7.4RC1