Intel machines running 32bit versions of Windows can address 4GB of memory, but not use it. PAE enables address space above 4GB. It's also required for DEP, and must also be supported by your hardware (e.g. chipset) and drivers. Why some people here are seeing all 4gb in the properties dialogue of 2K3 std, I don't get it. I thought I understood this issue, but obviously there are some real world experiences here showing otherwise.
http://blogs.msdn.com/dcook/archive/2007/03/25/who-ate-my-memory.aspx http://www.microsoft.com/whdc/system/platform/server/PAE/pae_os.mspx http://www.microsoft.com/whdc/system/platform/server/PAE/PAEdrv.mspx http://support.microsoft.com/kb/875352 (DEP) http://tinyurl.com/27obg7 (xp, but still relevant and excellent explanations) PAE on an OS that is limited to 4GB, is only because DEP requires it. Enabling DEP automatically enables PAE. Otherwise it (PAE) would be a useless feature on 2K/XP/2K3 std. The BIOS, video cards, memory, et al, all use address space. When you only have 2GB in the machine, there is a lot of address space left over and unused by the memory you don't have installed. When you put all 4GB in the machine however, then there isn't any address space left available for your installed components (video cards, BIOS, drives, et al.) which also use this address space, so something has to give. This is why you see less than 4GB typically. But then there are these people that are seeing the 4GB in Windows and it defy's what should really be happening as I understand it. Vista 32bit w/ SP1 will report installed memory and not useable memory. So people will see their 4GB, but not actually be able to use it. Weird. -- Mike Gill From: Ken Schaefer [mailto:[EMAIL PROTECTED] Sent: Wednesday, January 09, 2008 12:13 AM To: NT System Admin Issues Subject: RE: HP DL380 G5 and Win2k3 R2 Standard not showing maximum memory in OS http://www.microsoft.com/whdc/driver/kernel/mem-mgmt.mspx Cheers Ken From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Wednesday, 9 January 2008 4:21 PM To: NT System Admin Issues Subject: RE: HP DL380 G5 and Win2k3 R2 Standard not showing maximum memory in OS We currently have dozens of servers running all flavors of 32 bit OS and we see the full 4 GB give or take a few meg depending on the manuf. I have seen servers only show 3.5 and its always been a BIOS setting in our case that I remember. From: Ken Schaefer [mailto:[EMAIL PROTECTED] Sent: Tuesday, January 08, 2008 6:57 PM To: NT System Admin Issues Subject: RE: HP DL380 G5 and Win2k3 R2 Standard not showing maximum memory in OS Glen, You don't mention whether you are running x64 or x86 edition of Server 2003. Also, depending on the hardware you have the device you might only "lose" accesss to a few MB of RAM (or maybe none at all). My HP ML330 only loses about 60MB, so instead of 4096 it reports 4036, which looks very similar to 4GB of RAM. But you can disagree all you like - you'd still be wrong :-) Please read the memory management whitepaper I posted earlier if you 'd like all the details. Alternatively, just read the blog posts from Raymond Chen's blog if you want some quick information. Cheers Ken ~ Upgrade to Next Generation Antispam/Antivirus with Ninja! ~ ~ <http://www.sunbelt-software.com/SunbeltMessagingNinja.cfm> ~
