4gb is shown as 3.24 gb usable

thats odd, 64bit goes quite high on its memory tolerance

are you sure its 64bit sounds more like 32 bit :S

What motherboard? A LGA1156? 6 slots for DDR, or only 4?

You are apparently mistaken and must be using the 32 bit version.

Look under the memory tab in Resource Monitor. How much is "hardware reserved" in the "Physical Memory" graph?

That's reserved for things like BIOS ROM and memory mapped I/O (MIMO) -- for I/O to things like PCI cards.

You might explore your BIOS and see if there are options for memory mapping or shared memory.

Also, is it possible that memory might be allocated to on-board video even if it's disabled?

hi, I am confirmly using 64bit. . when i was using my integreted graphics the usable amount of ram was 3.86GB but when i installed my 9600gt it went down to 3.24GB . . i have DH55TC . . I also examined the video configuration in bios . . i lowerd the DVMT to 128M. I also enquired the hardware reserved in Resource monitor, there was 778mb was reserved . . how to solve it?? please help!!!

What if the board only supports 4 gb? Would that limit the hardware mapping to 4 gb?

What motherboard are you using?

There may also may be a memory remapping function in the bios somewhere that needs to be on. If not, the motherboard will map the hardware into a 4 gb window and gobble up some memory, just like a 32 bit os.

mobo supports upto 16gb . . cant get ur pint falcon . . . .

my mobo has a memory remapping feature, but its set by default to enabled

The memory remapping feature if you have it, and it is turned off, will usually only let 3 gig of memory be shown at boot. How much memory is showing up during the POST memory count/test?

If you have 4GB and Windows can see only 3.24GB, download ans install the VSuite Ramdisk Free Edition from http://www.romexsoftware.com/en-us/index.html, create a ramdisk of 768 MB using the "OS Invisible Memory" option, then set the Windows pagefile to that disk.

The person in a different forum seems to have the same kind of idea about memory reserved for hardware:

http://www.sevenforums.com/general-discussion/86886-32-...

I am not sure about this, but it seems to me that whether the OS is 64-bit or not, it still has to allocate 725-750 MB of memory for the hardware; my understanding is that the 8 TB that the OS can use as "addressable space" is only the ceiling of how much RAM you can put in the computer which the the RAM will actually use and it still has to allocate hardware resources of 725-750 MB, all of the hardware in the computer that needs to be addressed still being the same amount regardless of what OS you are using. What do you guys think?

This matter is trivial. I read somewhere that H/W reservation addr. should only takes 16 Kb or so.
Try reseating all memory sticks and reboots your system. Some people can solve it by this.