silverchair
Contributor
Contributor

Windows 2003 x32 Enterprise R2 SP2 cant see 4gig of ram

I have x6 servers. Windows 2003 x32 Enterprise R2 SP2 cant see 4gig of ram. They can only see 3.75 gig.

Obviously i have tried the /PAE and /3GB switches and they have made no difference what so ever.

Link below says enterprise can handle 64gb ram, what gives??

http://msdn.microsoft.com/en-us/library/aa366778.aspx

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9 Replies
NTurnbull
Expert
Expert

Clicky

Thanks,

Neil

Thanks, Neil
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Texiwill
Leadership
Leadership

Hello,

Moved to Virtual Machine and Guest OS forum.


Best regards,

Edward L. Haletky

VMware Communities User Moderator

====

Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education.

SearchVMware Blog: http://itknowledgeexchange.techtarget.com/virtualization-pro/

Blue Gears Blogs - http://www.itworld.com/ and http://www.networkworld.com/community/haletky

As well as the Virtualization Wiki at http://www.astroarch.com/wiki/index.php/Virtualization

--
Edward L. Haletky
vExpert XII: 2009-2020,
VMTN Community Moderator
vSphere Upgrade Saga: https://www.astroarch.com/blogs
GitHub Repo: https://github.com/Texiwill
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RParker
Immortal
Immortal

OK due to architectural modifications from Intel it's designed this way. Beneath the 4GB barrier, there is reserved RAM/ROM for certain video and controller systems. so when a machine is configured with 4GB of RAM you may only get 3.2 or 3.75 or some number in between, but it depends on the chipset and version of your ESX host and what it has, as to what the VM will be able to 'see'. There are NUMEROUS posts about this EXACT issue, and no matter who you talk to is 100% an Intel issue.

So yes 4GB = 3.2 ~ 3.75GB of RAM. If you give 5GB you should see ALL 5GB it's weird I know but it has to specifically do with 4GB of RAM.

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silverchair
Contributor
Contributor

So yes 4GB = 3.2 ~ 3.75GB of RAM. If you give 5GB you should see ALL 5GB it's weird I know but it has to specifically do with 4GB of RAM.

4GB = 3.75GB of RAM. If you give 5GB = 4.75gb ram, it is still reserving the 256mb for video and other hardware addresses.

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silverchair
Contributor
Contributor

Here is another question or thought. Say i make another Win 2003 ent server x64

exactly the same, exactly the same amount of ram 4.

x32 will see 3.75gig

x64 will see 4gig

Which will perform better in this situation?

one sees more ram, but does the x64 also have extra overhead. Will that negate any additional performances seen by having 256mb of extra ram.

or if that is in the unknown. If i have

x32 with 3.75gig

x64 with 3.75gig

which is better/faster?

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silverchair
Contributor
Contributor

is 256mb of ram always going to be reserved for video even in ESX VM environment?

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RParker
Immortal
Immortal

one sees more ram, but does the x64 also have extra overhead. Will that negate any additional performances seen by having 256mb of extra ram.

If you can go 64-bit that will be WAY better than 32-bit. No additional overhead, better performance, and backwards compatible with 32-bit programs. That's the best route for you, and apparently the 256 will always be reserved no matter what you do.. although with 5GB vs 4GB are you really going to notice 256 Meg RAM?

If 64-bit doesn't have this limitation and you can use it, I would use 64-bit instead in that case.

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silverchair
Contributor
Contributor

Thanks for everyones help so far...

no it wasnt a matter of noticing the difference but if i am committing 256 ram x all my servers that is being wasted i should just assign them 256mb less ram. then there is no problem and i get the most out of my hosts. freeing up 7.5 gig of ram.

second part of the problem is if i am licensed by Microsoft for VL Win 2003 ent x32 r2 i can just run VL Win 2003 ent x64 r2 with the same license no problems?

also

if i WAS running x64 will that be a problem with terminal servers, with say Office 2003 which is a 32 bit app it will emulate a 32 bit environment for it to run. So any performance gains obtained from x64 would possibly be negated by the emulation of all my x32 bit TS apps.

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Craig_Baltzer
Expert
Expert

With VL licensing you can run either 32 or 64 bit Windows Server 2003, its all the same license (different keys, but the same license). has the details (question # 7 in the "General" section)

32 bit apps will negate some of the performance gain from 64 bit TS, whether it negates all of the performance gain or not depends on the app and usage patterns (i.e. "try it and find out" is about the only answer)...

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