Win 7 64Bit install. 4GB RAM showing as (3.50GB usable)

  • Thread starter Thread starter Alan Kent
  • Start date Start date
A

Alan Kent

Hi All

I have successfully installed my MSDN 64Bit version of Windows 7 Ultimate on
a DELL Dimension 9100 PC.

The problem I am having is with the RAM. The PC has 4GB of ram that shows up
fine within the BIOS. When I go into the Windows 7 System Control Panel it
shows as 4.00GB (3.50 usable). I can understand this will happen with a
32bit operating system, but this is a new install of the 64bit version of
Windows 7 Ultimate. I have the latest BIOS version installed. My system spec
is as follows:

DELL Dimension 9100
Intell(R) Pentium(R) D CPU 2.80GHz 2.79GHz / Dual Processor
64Bit (Intel EM64T)
4 x 1GB DDR2 SDRAM

When I use the full 4GB the 7 System Control Panel shows as 4.00GB (3.50
usable).
When I remove 2GB the 7 System Control Panel shows as 2.00GB.

Is this a bug, and if so is there a workaround? Maybe this is normal and
should happen.

Please help
Alan
 
I don't think it's a bug, I think it's the limitations of the hardware.
According to the Dell documentation your hardware limit is 4GB. The
1/2GB lost may be taken up by the motherboard or assigned to the video,
or any number of reasons. I think you're just going to have to live
with what you've got.
 
To have all 4GB available to use you would have to find and enable a
Memory Remap setting in the BIOS. But I think the Dimension 9100 was
only sold with XP, a 32-bit OS, so the setting probably does not exist
even though the hardware is capable of using all 4GB.
 
If he really has a 32-bit only motherboard and cpu then how did he install
Win7 64-bit?
 
Jerry said:
If he really has a 32-bit only motherboard and cpu then how did he install
Win7 64-bit?
Click to expand...

Because the CPU supports 64bit, but the motherbord/chipset only has a
32bit address bus. Also, 32bit CPUs have supported 36bit addressing for
years, but that doesn't mean all boards supports it.
 
I have almost the exact same system specs in a Sony wuth the same chipset
running Vista 64. Where are you seeing the lower memory number ?
 
Jerry said:
If he really has a 32-bit only motherboard and cpu then how did he install
Win7 64-bit?
Click to expand...

The 945 Lakeport chipset does not support memory remapping.
It will take a 64 bit CPU, and run a 64 bit OS, as the data bus is
64 bits.
 
He does not have a 32bit motherboard he has a motherboard which will support
64 bit CPUs but which will not support more then 4MB of installed memory.
 
He does not have a 32bit motherboard he has a motherboard which will support
64 bit CPUs but which will not support more then 4MB of installed memory.
Click to expand...


Can I leap to the conslusion that if HP puts 6GB of RAM in a cheap
desktop and ships it with a 64 bit OS, the system is fully 64-bit
datapaths?

(Even video, which in this case is on-mobo in the G33 coprocessor
chip.)
 
Yes all 64 bit applications and drivers will use 64 bit datapaths.
Older 32 bit applications will continue to use 32 bit data paths.
 
Al Dykes said:
Can I leap to the conslusion that if HP puts 6GB of RAM in a cheap
desktop and ships it with a 64 bit OS, the system is fully 64-bit
datapaths?

(Even video, which in this case is on-mobo in the G33 coprocessor
chip.)



--
Al Dykes
News is something someone wants to suppress, everything else is
advertising.
- Lord Northcliffe, publisher of the Daily Mail
Click to expand...

Yes, but the amount of memory has nothing to do with
it. Even if there is only 1GB, the data bus width is still
64 bits.

The data bus became 64 bit with the introduction of the
Pentium back in 1993. Even a 32 bit OS makes full use of
the 64 bit data bus. The 64 bit data width allows two 32
bit instructions to be accessed simultaneously. This
increases CPU efficiency by allowing two instructions to
be processed in a single memory access cycle.
 
AFAIK the 64 bit compiler supports the creation of a single 64 bit
instruction that can combine 2 32 bit instructions.
If is not my understanding that a 64 bit OS automatically combines two 32
bit instructions into one 64 bit instruction. If it did then 32 bit
applications would not run slightly slower when being run a 64bit OS in
32bit emulation mode.
 
Curious said:
AFAIK the 64 bit compiler supports the creation of a single 64 bit
instruction that can combine 2 32 bit instructions.
If is not my understanding that a 64 bit OS automatically combines two 32
bit instructions into one 64 bit instruction. If it did then 32 bit
applications would not run slightly slower when being run a 64bit OS in
32bit emulation mode.

news:#[email protected]...
Click to expand...

I didn't say that a 64 bit OS combines two 32 bit instructions.

What I said was that the 64 bit data bus, which was introduced
with the Pentium, allows a 32 bit OS to make full use of the
64 bit data path by simultaneously accessing two 32 bit
instructions, side by side, in a single memory access cycle.
 
And what I said was that a 64 bit OS can not combine 2 instructions
contained in a 32 bit application and execute them in one cycle in a 64 bit
OS.
You are confusing the issues between the use of 64 bit compilers to execute
64 bit instructions and the ability of 32 bit applications to address more
then 4MB of address space which they can not do since the only use 32 bit
memory addresses.
 
While this article is aimed at game developers, it does explain the memory
issues around 4 GB in detail. You might find it useful:

http://www.gamasutra.com/view/feature/3602/sponsored_feature_ram_vram_and_.php

Standard 32-bit applications run exactly the same on a x64 CPU and 64-bit
version of Windows as they would on a standard version of Windows. The main
difference is that the OS itself can utilize extra memory for multitasking.
Some specially enabled 32-bit applications can make use of some extended
memory beyond what it could on a 32-bit version of the OS. The main point of
x64 technology is that 32-bit applications just work while enabling new
classes of applications.

x64 native applications are compiled with x64 specific instructions and
assumptions. If you are interested in the technical details , see:

DirectX Technical Article - 64-bit programming for Game Developers
http://msdn.microsoft.com/en-us/library/bb147385(VS.85).aspx

or the Gamefest 2008 presentation:
http://www.microsoft.com/downloads/...6A-EE8A-406A-A5AE-9E065343CD06&displaylang=en
 
Back
Top