Win64 does not support /3GB switch.  It isn’t need in 64-bit environment.

http://support.microsoft.com/kb/294418/

Copied from support note:
System PTEs

A pool of system Page Table Entries (PTEs) that is used to map system pages such as I/O space, Kernel stacks, and memory descriptor lists. 64-bit programs use a 16-terabyte tuning model (8 terabytes User and 8 terabytes Kernel). 32-bit programs still use the 4-GB tuning model (2 GB User and 2 GB Kernel). This means that 32-bit processes that run on 64-bit versions of Windows run in a 4-GB tuning model (2 GB User and 2GB Kernel). 64-bit versions of Windows do not support the use of the /3GB switch in the boot options. Theoretically, a 64-bit pointer could address up to 16 exabytes. 64-bit versions of Windows have currently implemented up to 16 terabytes of address space.

 

 

Allen,

 

Does this hold true for 64-bit Windows as well? Until seeing this thread I was unaware of the /3GB switch available for windows. It sounds analogous to compiling in the hugemem kernel in Linux. Or are the two unrelated? On Technet so far the only document I have found is the 32-bit Oracle Database Platform Guide, chapter 1. Can you point out a good source of information on this please.

 

Thanks.

Bill Wagman
Univ. of California at Davis
IET Campus Data Center
wjwagman@ucdavis.edu
(530) 754-6208

 

From: oracle-l-bounce@freelists.org [mailto:oracle-l-bounce@freelists.org] On Behalf Of Allen, Brandon
Sent: Monday, July 16, 2007 3:07 PM
To: saints.richard@gmail.com; oracle-l@freelists.org
Subject: RE: Oracle on Windows 2000 AS with /3GB flag

I always use the /3G flag on all Windows database servers - for both Oracle and SQL Server.  I've used it several times on different combinations of Windows, SQL & Oracle versions and never had any problems.

 

Regards,

Brandon

Privileged/Confidential Information may be contained in this message or attachments hereto. Please advise immediately if you or your employer do not consent to Internet email for messages of this kind. Opinions, conclusions and other information in this message that do not relate to the official business of this company shall be understood as neither given nor endorsed by it.