3G ram for SQL server

Hi,
I need help with right solution.
Server box: 4GBs RAM, SQL 2000 Enterprise, Windows 2003
server Enterprise.
I want SQL server have 3GB Ram. Please tell me which one
is right. (and reason if possible)
1. /3GB switch
2. /3GB switch and enable AWE
3. /3GB switch and enable AWE and /PAE
4. /3GB switch and /PAE
5. Enable AWE
Thanks
Mike32-bit address space is limited to 4 GB of addressable memory (real or
virtual). Every process is mapped into a 4 GB virtual space. This space is
split, by default, between 2 GB of Kernel mode (or protected) and 2 GB of
User mode (or private) address space. The /3GB switch changes the partition
to 1 GB for Kernel mode and 3 GB for User mode.
To address more than 4 GB of memory, you need a bigger register. The /PAE
switch changes the memory register from a 32-bit to a 36-bit register, thus,
allowing you to potentially address 64 GB of virtual memory. You can set
this when you have at least 3 GB of physical ram, but it really isn't useful
until you have at least 4 GB or more of physical ram. An interesting point
here, in order to address more than 16 GB of memory, the Kernel will need at
least 2 GB to manage it. So, when using more than 16 GB of memory, you need
to remove the /3GB switch.
/PAE is only useful for the OS or applications that make use of special
extended memory API calls. SQL Server does, but only in AWE mode. So, to
address more than 3 GB of memory, SQL Server needs to be in AWE mode.
Between the 3 GB and 4 GB physical memory space you can use the /3GB switch
and AWE to allocate SQL Server 4 GB of memory. To go any larger, however,
AWE will require that the /PAE switch to also be set.
Now, when not in AWE mode, SQL Server uses dynamic memory allocation and, if
required, could address up to 4 GB without it. However, maximum would be 3
GB of physical ram and 1 GB of pagefile space.
When you go AWE, SQL Server grabs the MAX SERVER MEMORY and partitions as
much of it to the active Buffer Pool, the rest is left for inactive data
pages. The point is that most of it is physical, not virtual.
So, in your case, the /3GB switch should be set. However, there is no need
to use AWE and, therefore, no need to set the /PAE switch.
Sincerely,
Anthony Thomas
"Mike" wrote:

> Hi,
> I need help with right solution.
> Server box: 4GBs RAM, SQL 2000 Enterprise, Windows 2003
> server Enterprise.
> I want SQL server have 3GB Ram. Please tell me which one
> is right. (and reason if possible)
> 1. /3GB switch
> 2. /3GB switch and enable AWE
> 3. /3GB switch and enable AWE and /PAE
> 4. /3GB switch and /PAE
> 5. Enable AWE
> Thanks
> Mike
>|||I'd opt for option #1 since this will allow you to use 3GB for SQL Server
plus 1GB for the OS. PAE is only needed if you have over 4GB RAM.
AWE memory access is more expensive than regular memory addressing so I
wouldn't go there unless you had more memory and your performance tests
demonstrate that the additional memory access costs are outweighed by the
decreased i/o costs.
Hope this helps.
Dan Guzman
SQL Server MVP
"Mike" <anonymous@.discussions.microsoft.com> wrote in message
news:1b1d01c4c789$e500d320$a501280a@.phx.gbl...
> Hi,
> I need help with right solution.
> Server box: 4GBs RAM, SQL 2000 Enterprise, Windows 2003
> server Enterprise.
> I want SQL server have 3GB Ram. Please tell me which one
> is right. (and reason if possible)
> 1. /3GB switch
> 2. /3GB switch and enable AWE
> 3. /3GB switch and enable AWE and /PAE
> 4. /3GB switch and /PAE
> 5. Enable AWE
> Thanks
> Mike
>