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Windows XP and RAM 3.5GB+
Is there way to enable 4 GB RAM in 32-bit Windows OS?

I installed 4GB of RAM on my Windows 7 Ultimate 32-bit (it used to have only 2GB).

But it says only 3GB usable, and I still often get a "Not enough memory" problem on Photoshop.

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Is there any way to make it utilise the full 4GB?

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migrated from Jan 28 '11 at 10:56

This question came from our site for system and network administrators.

marked as duplicate by Joe Taylor, DMA57361, William Hilsum, BinaryMisfit Jan 28 '11 at 11:38

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

up vote 0 down vote accepted

See if PAE can help you:

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PAE does not increase the addressable limits on Windows. Whilst PAE can, Windows goes out of its way to block that functionality. – Matthieu Cartier Jan 28 '11 at 11:08
This tool does it: (Thanks to k00x and Breakthrough) – Aximili Feb 6 '11 at 11:57

Quite simply, you can't use it, 32bit cannot access above 3gig due to limitations of the 32bit addressing, only 64bit OS with a 64bit CPU can access above this.

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That's Not full true. Many Windows Server Version of 32 bits (Enterprise and datacert) can use PAE and other SO tools to address much more memory. BUT in "simple" SO for desktop, Your answer is 100% true. – Carlos Garcia Jan 28 '11 at 10:49
Ubuntu also addresses all four gigabytes using PAE. – oKtosiTe Jan 28 '11 at 11:28
Windows used to but as usual crappy drivers ruined the day and so after XP SP2 this was disabled. – Mark Sowul Mar 5 '11 at 1:53

You have a 64 bits CPU, why did you bough a 32 bit operating system ?

You need Windows 7 64 bits and you can use much more memory and it will run faster.

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Only in very specific scenarios will any performance increase be noticeable. Video encoding is one example. In most cases the difference is negligible. – oKtosiTe Jan 28 '11 at 11:32
Of course it depends on the application but still faster. – Dragos Jan 28 '11 at 11:40
Because there might still be software that I need that is not compatible with 64-bit yet... – Aximili Feb 5 '11 at 13:31
You can run that in a 32-bit VM. – Jamie Hanrahan Aug 3 '14 at 19:47

Is there any way to make it utilise the full 4GB?

Install 64-bit Windows. In X86 Windows virtual address space for each 32-bit process limit 3Gb.

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"Install 64 bit Windows" is the right answer but the 3 GB virtual address space limit has nothing to do with it. This is a limit on physical addresses, not virtual. – Jamie Hanrahan Aug 3 '14 at 19:14

32bit use above 3gig due to limitation of 32bit addressing; only a 64 bit os can unless you run a server edition with PAE. Do you have a x64 CPU?

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This actually says the limit on x86 is 4GB And a friend of mine can see 3.25GB out of his 4GB on his Windows 7 32-bit – Aximili Feb 5 '11 at 13:32
It's called the "3 GB barrier" but where it actually is depends on what PCI hardware you have using up physical address space. Put in a much smaller video card, you'll find you have more RAM usable. Larger video cards, or more of them, you'll get less RAM. I have one machine, a dual-socket Xeon monster with a video card on each node. Just to see what would happen I installed Win7 x86 on it before installing my real OS. It saw only 2 GB! – Jamie Hanrahan Aug 3 '14 at 19:17

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