32-bit windows showing 3.24GB of ram instead of 8GB

[ishti91]

i am using windows 7 32 bit os.i ve installed 8gb of ram bt in system it shows only 3.24gb is usable.why?

 

[Dark Lord of Tech]

32 bit windows will only recognize about 3.25 to 3.75.64 bit will recognize alot more!

If you install 64 bit windows it will see the whole 8gb!

 

[davcon]

^+1 Exactly!

 

[edmond419]

You need to upgrade to a 64-bit Windows.

The nature of 32-bit systems can only support up to 3GB of RAM

 

[Herr_Koos]

i am using windows 7 32 bit os.i ve installed 8gb of ram bt in system it shows only 3.24gb is usable.why?

In case you are interested in the math: A 32bit system allows 2^32 = 4 294 967 296 bits of addressable memory space. That gets you a theoretical limit of 4096MB of RAM. Some of it is used up by the system for various other purposes, hence 32bit Windows only supports 3.xx MB.

As stated by above posters, switching to 64bit Windows will solve your problem. The upper limit then becomes 2^64 = 1.84467441 × 10^19, which is probably more than you will need for a while..

Just be aware that moving to 64bit will require a clean installation. So make backups and re-install.

 

[fowang]

For anyone else who might find this problem, read the system specs before installing an OS it will help avoid heart ache.

 

[cooky]

I don't know how good your German is but you can find a patch here: http://www.unawave.de/windows-7-tipps/32-bit-ram-sperre.html. It makes a copy of your kernel and removes the DDR RAM blocker.
You'll have the possibility to either boot win7 with the patched kernel or the standard installation.
Worked for me.
I couldn't find an English page on the topic, sorry for that.

 

[quantumdawn]

There really isn't an easy fix like installing a "ram unlocker". As explained above by Herr_koos, the limit to 3.25gb is a hard limit set by the 32-bit OS and not a software limitation that can be bypassed by a patch.

Back up your system, and re-install the 64-bit version.

 

[mathew7]

Blame MS for this, because since introduction of no-execute bit (XP SP2) all CPU's with NX-bit support (newest P4s and AMD 64s) enter PAE-enabled mode (which could enable up to 2^52=4PB of RAM).
Advanced and enterprise versions of 32-bit Windows can access up to 64GB RAM (again a MS limitation).

 

[mathew7]

Blame MS for this.
PAE is available since 1996 (Pentium Pro), and allow for up to 2^52 bytes access of 32-bit processors.
NX-bit was introduced with AMD 64 and newest P4 processors and was used starting with XP SP2.
So basically, XP SP2 and newer Windowses use PAE modes if the CPU offers NX-bit.
PS: why you are not seeing 4GB is because PCI devices are limited to 32-bit address space (4GB), so they are mapped over existing RAM. The overlapped RAM can be remapped to "after the end" (8GB in your case), but you are still limited to 4GB.

 

[Herr_Koos]

you can try overclocking the 32 bit to 64 bit.

I'm hoping that was a joke...

 

[Herr_Koos]

Blame MS for this, because since introduction of no-execute bit (XP SP2) all CPU's with NX-bit support (newest P4s and AMD 64s) enter PAE-enabled mode (which could enable up to 2^52=4PB of RAM).
Advanced and enterprise versions of 32-bit Windows can access up to 64GB RAM (again a MS limitation).

Quote from Wikipedia:

Microsoft Windows implements PAE if booted with the appropriate option, but current 32-bit desktop editions enforce the physical address space within 4GB even in PAE mode. According to Geoff Chappell, Microsoft limits 32-bit versions of Windows to 4GB due to a licensing restriction, and Microsoft Technical Fellow Mark Russinovich says that some drivers were found to be unstable when encountering physical addresses above 4GB. Unofficial kernel patches for Windows Vista and Windows 7 32-bit are available that break this enforced limitation, though the stability is not guaranteed.

Switching to a proper 64-bit system is much safer than loading some dodgy kernel patch that might stuff up the entire system.

 

[cooky]

I have been running the 'dodgy kernel patch' for 8 months now and didn't have a problem so far. Just saying.

 

[misry]

you can try overclocking the 32 bit to 64 bit.

Really? Really. You typed that out loud?

Until you go to a 64-bit OS use the "extra" RAM in a RAM disk for your swap file and temp files. http://www.techsnack.net/gavotte-ramdisk-free-virtual-hardisk

 

[Herr_Koos]

Fair enough, but I would not recommend it based on one PC running stable.