Hi,I have installed windows server 64 bit edition on a machine with 4 GB RAM. If I view system properties from ControlPanel->System it showsSystem------------------------------------CPU: Intel Core 2 Duo E4500 @ 2.25 GHzMemory(RAM): 4.00 GBSystem Type: 64-bit operating SystemHowever if see in Task Manager -> Performance TabIt showsPhysical Memory (MB)Total 3318Cached 805Free 1771Why does the Task Manager show only 3318 MB as Total Physical Memory where I have 4 GB RAM. I am definitely using 64 bit OS which is supposed to support 4 GB RAM

What kind of server is this? This might be a hardware problem. I just checked my Dell 2950 servers that have Windows x64 installed and 4GB of RAM and Task Manager reports the memory correctly. What application are you planning on running under x64, by the way?

seen this on some servers here too. theres an option in the servers bios to support more than 3gb ram, if not you check if theres a bios update available. check the serversP.O.S.T. it should also display 3gb only.

I have the same problem with my Windows 2008 64bit. I have 6GB installed . My bios shows the entire 6Gb available in the memory but Windows shows only 3318 Mb on the task manager. How can I make use of entire memory. If I can't use then what is the use of 64bit software ?.

I have the exact same issue on a 2008 32bit Enterprise Ed. 8 gb installed and task manager only shows around 3 gb available. On the system properties page the 8 gb is displayed correctly and of course the bios shows the 8 gb.as well.The server is a brand new HP Proliant DL360 G5.

I have spend the most of 3 days now with this problem. I had a Window 2003 Ent. ed. 32 bit running on the hardware. That installation showed 8 GB of memory in task manager. I wanted to take full advantage of the systems 64 bit capability, so I went ahead and installed the 2008 server 64 bit version. Hyper-V suggested that I enabled the No-execution Memory protection switch in BIOS in order for Hyper-V to work. I have a feeling that Windows 2008 was able to see all 8 GB at that point, but thats not conclusive. Anyway I found out that I was missing memory when I started installing VM's. Some Internet pages suggested windows updates to be the problem others that switches such as /PAE or /3GB be used. The switches don't apply to 64 bit systems, but I tried the bcdedit /set PAE forceenable anyway - no diffference. I tried disabling the No-execution Memory protection - no difference. I tried reinstalling Windows 2008 - no difference. I tried installing Windows 2003 R2 STD 64 bit - no difference. All updates installed and still no difference. Server 2008 show 8GB in system but not in Task Manager Server 2003 show 3.25 GB in system and 3.4 GB in Task Manager I hope someone will be able to provide an answer for this soon. It apears that a lot of people have this problem on many Windows platforms, but so far I have not been able to find a single workaround or solution.

Solved Solution came to me when searching the web -the word "Remap" continuously appeared. Story continue... After having flashed the BIOS all the way back to 1.40 (current 1.70) on my Asus board, without success, I went back to 1.70 and looked for Remap Memory wich I enabled. After reboot the taskmanager showed 7.984 GB Memory After disabling the No Execute in BIOS Hyper-V was running full trottle.