Hello Experts

We have an active/passive failover cluster running on some decent IBM X
Series servers, quad x64 Xeons with 16 Gb of RAM.

We upgraded each server to 64Gb.  As the server started eating into the new
RAM, performance gradually got worse.  When we got to about 50Gb consumed we
had to stop and start the service due to the number of complaints from our
users.  The cycle repeated.

There are three databases, two under 1Gb and not used much, and one at about
47Gb, used intensively.  Performance had been "ok", with ups and downs as
and when large reports where running etc.

I panicked when I noticed the AWE checkbox was not ticked in the memory
properties, then breathed out when I learned this is not required on X64 due
to it's ability to be able to address all the RAM normally.  I did learn
however about the "lock pages in memory" privilege that _wasn't_ set-up for
the SQL server login accounts, so set that up and restarted SQL Server.  (As
these servers are in a FO cluster, this is set in Domain Policy Editor, not
gpedit.msc as M$ state. grpedit does not allow you to edit this setting on
my servers.)

It made no difference.  I had thought that perhaps there was a paging issue
and that this would fix it.  I allocated a min of 1Gb and a max of 56Gb,
leaving 8Gb for anything else.  I checked pages/sec in performance monitor
and there was nothing doing.

The problem occurred again, after a while, once the server had started
eating in to some memory, the performance tails right off and the server
slows right down.

I have now removed the lock pages in memory privilege, and fixed the maximum
memory at 16Gb, (the amount that was previously installed), and touch wood,
it seems to be holding up.

Can anyone shed any light on what might be causing this?  Surely we should
be able to whack the RAM in and let SQL Server eat it's heart out.  You can
imagine that the RAM was a considerable investment and it's turned out to be
a complete waste of money, if not worse ... it's damaging our business!

Windows Server 2003 R2 Enterprise x64 Edition
SQL Server 9.00.1399.06 RTM Standard Edition (64-bit)

According to this we don't need Enterprise edition of SQL Server
(http://www.microsoft.com/Sqlserver/2005/en/us/compare-features.aspx).

The only odd thing I have noticed is that when we were running with 56Gb
maximum, the counter for current memory was 36 or so and the target memory
was 59 (GB).  Why would it target more than it was using if more was
available?

I really hope you can help as I am totally in the dark.  Everything I read
says how SQL loves memory, you can't have too much memory, how wonderful SQL
memory management is. For me, it's been a disaster.

Thanks and regards

Mike