postgresql +AMD64 +big address spaces - does it work?

If I bought one of these boxes/OS combos as a postgresql database server,
would postgresql be able to make the best use of it with a huge (e.g. 40GB)
database?

Box: HP ProLiant DL585, with 4 AMD64 CPUs and 64GB of RAM. (other
vendor options also exist)
OS: SUSE enterprise 8 linux for AMD

(links to product info at bottom)

e.g. Could postgresql make use of most of this address space to map a huge
database (say 40GB) all paged into RAM at once?

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According to Suse, a process running on such a setup can individually
address 0.5 terabytes of address space, and at any one point, with the
hardware above, up to 64GB (minus a bit!) of this address space could be
paged into physical memory at any one time.
----

According to the docs I could find, I just need to do the following:

1. set postgresql.conf->shared_buffers to a value like (40GB/8KB),

2. Check cat /proc/sys/kernel/shmmax is big enough, or successfully increase
it to > 40GB

From experience that's a long way from knowing it will work. Does anyone
have any experience at all with such big memory configurations?

Many thanks,
Andy

______
My references:
Suse: www.suse.com/amd64 and
www.suse.com/en/business/products/server/sles/sles8_amd64.pdf
HP: http://h18004.www1.hp.com/products/servers/proliantdl585/index.html