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G4, 4 Gb and PAE switch

Igor Karasik
Honored Contributor

G4, 4 Gb and PAE switch

Hi,
In business support document
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=PSD_EL041214_CW01
we can see:
"The new System ROM releases will require that PAE mode be enabled with exactly 4 GB of memory installed for certain 32-bit versions of the Microsoft Windows operating systems if the remapped memory above 4 GB is to be used. However, HP recommends that this memory not be used due to the performance loss that occurs when using PAE mode"
I have some questions related:
-How much performance loss occurs?
I didn't find any Microsoft/HP documents about this issue
-Is there are any ways to disable PCI Express ?
-PAE switch doesn't work with windows 2003 standard edition. So, if we buy G4 servers we will need to buy windows 2003 enterprise licenses for each G4 server, even if we don't need enterprise features. A little strange.

Thanks, Igor
2 REPLIES
Basil Vizgin
Honored Contributor

Re: G4, 4 Gb and PAE switch

PAE does work with w2k3 standart (also as XP SP2). So customer can use all of 4GB of memory with memory remap.
You even can use /3GB switch, but with note:
---------------
Caution Microsoft supports using the /3GB switch in Windows Server 2003, Standard Edition in a production environment for use by Active Directory. For other applications, Microsoft supports using the /3GB switch in Windows Server 2003, Standard Edition only in a production environment if the application vendor has tested in this environment and if the vendor is willing to support the customer who is using this functionality. Microsoft Exchange Server 2003 and Microsoft SQL Server 2000 are supported in production using this functionality.
http://www.itnewsgroups.net/link.aspx?url=http://support.microsoft.com/default.aspx?scid=kb;en-us;291988
-----------
Once I read that performance gain is no more than 10-15%, but never found acknowledgement.
I did not find any way to disable PCI-E.
And this is not only the question of PCE-E, note exists for DL740 without PCI-E with same problem.
Such memory-consumption behaviour is limitation of PC architecture when periphery need some space for transfer data.
Igor Karasik
Honored Contributor

Re: G4, 4 Gb and PAE switch

Basil, thanks for the answer - by mistake I assign only 4 point, I intend to assign more.

I open this thread one year ago.
Now situation with PAE mode is different:
- PAE switch is enable by default in windows 2003 sp1 (all editions) if CPU support DEP.
- exchange 2003 now support PAE mode
- and windows 2003 x64 edition occupies computer market