Scalability in postgres

HI.

Someone had some experience of bad performance with postgres in some server
with many processors?

I have a server with 4 CPUS dual core and gives me a very good performance
but I have experienced problems with another server that has 8 CPUS quad
core (32 cores). The second one only gives me about 1.5 of performance of
the first one.

Monitoring (nmon, htop, vmstat) see that everything is fine (memory, HD,
eth, etc) except that processors regularly climb to 100%.

I can see that the processes are waiting for CPU time:

vmstat 1

procs -----------memory---------- ---swap-- -----io---- --system--
-----cpu------
r b swpd free buff cache si so bi bo in cs us sy id
wa st
0 0 0 47123020 117320 17141932 0 0 8 416 1548 2189 1 1
99 0 0
0 0 0 47121904 117328 17141940 0 0 8 148 1428 2107 1 1
98 0 0
0 0 0 47123144 117336 17141956 0 0 8 172 1391 1930 1 0
99 0 0
0 0 0 47124756 117352 17141940 0 0 8 276 1327 2171 1 1
98 0 0
0 0 0 47118556 117360 17141956 0 0 0 100 1452 2254 1 1
98 0 0
2 0 0 47120364 117380 17141952 0 0 8 428 1526 2477 1 0
99 0 0
1 0 0 47119372 117388 17141972 0 0 0 452 1581 2662 1 1
98 0 0
0 0 0 47117948 117396 17141988 0 0 16 468 1705 3243 1 1
97 0 0
0 0 0 47116708 117404 17142020 0 0 0 268 1610 2115 1 1
99 0 0
0 0 0 47119688 117420 17142044 0 0 0 200 1545 1810 1 1
98 0 0
318 0 0 47116464 117440 17142052 0 0 0 532 1416 2396 1 0
99 0 0
500 0 0 47115224 117440 17142052 0 0 0 0 1118 322144 91
5 4 0 0
440 0 0 47114728 117440 17142044 0 0 0 0 1052 333137 90
5 5 0 0
339 0 0 47114484 117440 17142048 0 0 0 0 1061 337528 85
4 11 0 0
179 0 0 47114112 117440 17142048 0 0 0 0 1066 312873 71
4 25 0 0
5 1 0 47122180 117468 17142028 0 0 192 3128 1958 136804 23
2 75 1 0
3 0 0 47114264 117476 17142968 0 0 608 5828 2688 4684 7 2
89 2 0
0 1 0 47109940 117484 17142876 0 0 512 5084 2248 3727 3 1
94 2 0
0 1 0 47119692 117500 17143816 0 0 520 4976 2231 2941 2 1
95 2 0

Have postgres problems of lock or degradation of performance with many
CPU's?
Any comments?

RH 5.2. PG 8.3.6 and 64 bits.

thanks for the reply
regars ...