AWE vs PAE

guys,
what is the difference between AWE and PAE?PAE allows the OS to use more than 4GB of memory. AWE allows the
application to use more than 4GB.
Andrew J. Kelly SQL MVP
"rupart" <rupart@.discussions.microsoft.com> wrote in message
news:7D318157-43B8-49AD-9DF7-F38F6ABEEA03@.microsoft.com...
> guys,
> what is the difference between AWE and PAE?|||for SQL server, shd i enable PAE or AWE? Can both be enabled at the same tim
e?
"Andrew J. Kelly" wrote:

> PAE allows the OS to use more than 4GB of memory. AWE allows the
> application to use more than 4GB.
> --
> Andrew J. Kelly SQL MVP
>
> "rupart" <rupart@.discussions.microsoft.com> wrote in message
> news:7D318157-43B8-49AD-9DF7-F38F6ABEEA03@.microsoft.com...
>
>|||AWE is a SQL Server setting (sp_configure) and PAE is an operating system se
tting (BOOT.INI). If you
want SQL Server to utilize > 4GB memory, you need both settings.
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://www.solidqualitylearning.com/
"rupart" <rupart@.discussions.microsoft.com> wrote in message
news:82A723DF-8EEA-431B-8669-79146E1DCA1D@.microsoft.com...[vbcol=seagreen]
> for SQL server, shd i enable PAE or AWE? Can both be enabled at the same t
ime?
> "Andrew J. Kelly" wrote:
>|||in that case...in a server with 5G of ram
should i put the /AWE /PAE swith in the same line in the boot.ini?
For the OS, i can see under system mgmt that 5G is enabled. How abt for sql?
how do i check it has 5G? Also, is there any significant on it? The
performance shd be better i suppose
Thank you
"Tibor Karaszi" wrote:

> AWE is a SQL Server setting (sp_configure) and PAE is an operating system
setting (BOOT.INI). If you
> want SQL Server to utilize > 4GB memory, you need both settings.
> --
> Tibor Karaszi, SQL Server MVP
> http://www.karaszi.com/sqlserver/default.asp
> http://www.solidqualitylearning.com/
>
> "rupart" <rupart@.discussions.microsoft.com> wrote in message
> news:82A723DF-8EEA-431B-8669-79146E1DCA1D@.microsoft.com...
>
>|||boot.ini should have something like this:
multi(0)disk(0)rdisk(0)partition(2)\WIND
OWS="Windows Server 2003,
Enterprise" /fastdetect /pae /3gb
(The /3gb switch is not necessary, but for a box with 5gb of RAM it'll
provide a little more to the apps, i.e. SQL Server.)
To check the amount of physical RAM the OS is seeing you can just check
the Performance tab in task manager.
To turn on AWE memory for SQL Server you use the sp_configure stored
proc (in Query Analyzer for example):
exec sp_configure 'awe enabled', 1
reconfigure
go
Then you have to restart the SQL instance as the AWE setting only takes
affect on server startup. Also, when SQL Server is using AWE memory, it
cannot use dynamic memory management. It *will not swap pages out of
memory *if another app requests memory and the OS doesn't have enough to
satisfy the request (unlike the SQL dynamic memory manager). So you
should specify a "max server memory" amount with sp_configure. For
example, on your 5GB box, if you wanted to allocate 4GB to SQL and the
remaining 1GB to the OS & other apps, you would do this in QA:
exec sp_configure "max server memory", 5120
reconfigure
go
All this is documented in SQL BOL:
http://msdn.microsoft.com/library/d... />
g_3stg.asp
To see how much memory SQL Server is currently consuming you can open
the System Monitor (perfmon.exe) and add the counter: SQLServer:Memory
Manager | Total Server Memory (KB). SQL BOL has a lot of good stuff on
AWE & memory management.
HTH
*mike hodgson*
/ mallesons stephen jaques/
blog: http://sqlnerd.blogspot.com
rupart wrote:
[vbcol=seagreen]
>in that case...in a server with 5G of ram
>should i put the /AWE /PAE swith in the same line in the boot.ini?
>For the OS, i can see under system mgmt that 5G is enabled. How abt for sql
?
>how do i check it has 5G? Also, is there any significant on it? The
>performance shd be better i suppose
>Thank you
>"Tibor Karaszi" wrote:
>
>|||does /3g means the system will allocate 3g for system and the rest for
sql(that is after enabling thru AWE, rite?)?
yeah, good link...thank you
"Mike Hodgson" wrote:

> boot.ini should have something like this:
> multi(0)disk(0)rdisk(0)partition(2)\WIND
OWS="Windows Server 2003,
> Enterprise" /fastdetect /pae /3gb
> (The /3gb switch is not necessary, but for a box with 5gb of RAM it'll
> provide a little more to the apps, i.e. SQL Server.)
> To check the amount of physical RAM the OS is seeing you can just check
> the Performance tab in task manager.
> To turn on AWE memory for SQL Server you use the sp_configure stored
> proc (in Query Analyzer for example):
> exec sp_configure 'awe enabled', 1
> reconfigure
> go
> Then you have to restart the SQL instance as the AWE setting only takes
> affect on server startup. Also, when SQL Server is using AWE memory, it
> cannot use dynamic memory management. It *will not swap pages out of
> memory *if another app requests memory and the OS doesn't have enough to
> satisfy the request (unlike the SQL dynamic memory manager). So you
> should specify a "max server memory" amount with sp_configure. For
> example, on your 5GB box, if you wanted to allocate 4GB to SQL and the
> remaining 1GB to the OS & other apps, you would do this in QA:
> exec sp_configure "max server memory", 5120
> reconfigure
> go
> All this is documented in SQL BOL:
> http://msdn.microsoft.com/library/d...>
fig_3stg.asp
> To see how much memory SQL Server is currently consuming you can open
> the System Monitor (perfmon.exe) and add the counter: SQLServer:Memory
> Manager | Total Server Memory (KB). SQL BOL has a lot of good stuff on
> AWE & memory management.
> HTH
> --
> *mike hodgson*
> / mallesons stephen jaques/
> blog: http://sqlnerd.blogspot.com
>
> rupart wrote:
>
>|||The other way around. 3 GB for the application and 1 GB for the system.
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://www.solidqualitylearning.com/
"rupart" <rupart@.discussions.microsoft.com> wrote in message
news:4944B057-1DC7-4638-BB88-9040FDCC9B9F@.microsoft.com...[vbcol=seagreen]
> does /3g means the system will allocate 3g for system and the rest for
> sql(that is after enabling thru AWE, rite?)?
> yeah, good link...thank you
> "Mike Hodgson" wrote:
>|||Oops - slight typo in my "max server memory" statement. To set a max
server memory of 4GB you would run:
exec sp_configure "max server memory", 4096
reconfigure
go
The 5120 figure I included in my previous post would try to set it at
5GB (not 4GB).
*mike hodgson*
blog: http://sqlnerd.blogspot.com
Mike Hodgson wrote:
[vbcol=seagreen]
> boot.ini should have something like this:
> multi(0)disk(0)rdisk(0)partition(2)\WIND
OWS="Windows Server 2003,
> Enterprise" /fastdetect /pae /3gb
> (The /3gb switch is not necessary, but for a box with 5gb of RAM it'll
> provide a little more to the apps, i.e. SQL Server.)
> To check the amount of physical RAM the OS is seeing you can just
> check the Performance tab in task manager.
> To turn on AWE memory for SQL Server you use the sp_configure stored
> proc (in Query Analyzer for example):
> exec sp_configure 'awe enabled', 1
> reconfigure
> go
> Then you have to restart the SQL instance as the AWE setting only
> takes affect on server startup. Also, when SQL Server is using AWE
> memory, it cannot use dynamic memory management. It *will not swap
> pages out of memory *if another app requests memory and the OS doesn't
> have enough to satisfy the request (unlike the SQL dynamic memory
> manager). So you should specify a "max server memory" amount with
> sp_configure. For example, on your 5GB box, if you wanted to allocate
> 4GB to SQL and the remaining 1GB to the OS & other apps, you would do
> this in QA:
> exec sp_configure "max server memory", 5120
> reconfigure
> go
> All this is documented in SQL BOL:
> http://msdn.microsoft.com/library/d...
fig_3stg..asp
> To see how much memory SQL Server is currently consuming you can open
> the System Monitor (perfmon.exe) and add the counter: SQLServer:Memory
> Manager | Total Server Memory (KB). SQL BOL has a lot of good stuff
> on AWE & memory management.
> HTH
> --
> *mike hodgson*
> / mallesons stephen jaques/
> blog: http://sqlnerd.blogspot.com
>
> rupart wrote:
>