Maximum RAM Read on 32 bit systems

[blaquee]

Hi, I was just wondering about the 32bit RAM range, if im not mistkaen a 32bit system can recognize up to 4GB of ram right?

If so how much does Windows 7 have reserved? because i have 4gb ram installed but windows only reveals 2.99GB RAM useable in the control panel. Anyone can clear this up?

 

[Antman]

Hi, I was just wondering about the 32bit RAM range, if im not mistkaen a 32bit system can recognize up to 4GB of ram right?

If so how much does Windows 7 have reserved? because i have 4gb ram installed but windows only reveals 2.99GB RAM useable in the control panel. Anyone can clear this up?

The RAM that you do not see is mapped for hardware resources. 32-bit OS can address 4GB. You will be better served by reading what Wikipedia has available.

 

[sup3rsprt]

2.99GB is probably all the RAM you will need, as long as you don't let your system go overboard with running processes. If you want to use the full 4GB, you'll need 64-bit Windows.

 

[toughbook]

32 Bit Os systems can only use 3.2 of Ram.

 

[Antman]

Here we go again.

 

[Tews]

Its not how much RAM that 32bit is able to address, rather its the amount MS licenses to be addressed ...

 

[zigzag3143]

32 Bit Os systems can only use 3.2 of Ram.

Um, no. most 32 bit computers fall somewhere between 3.25 and 3.5 gigs. I will not get that discussion started again

 

[y0himba]

Its not how much RAM that 32bit is able to address, rather its the amount MS licenses to be addressed ...

This is correct.

 

[logicearth]

Yeah you know it is the hardware...

 

[y0himba]

Geoff Chappell, Software Analyst - Viewer

PAE baby, PAE.

 

[logicearth]

PAE is already enabled by default on Intel Core Processors, it is required to use DEP. However PAE is not for accessing 4 GB, it is for accessing OVER 4 GB. The problem is not 32 bit addressing but hardware address reservations.

 

[y0himba]

That 32-bit editions of Windows Vista are limited to 4GB is not because of any physical or technical constraint on 32-bit operating systems. The 32-bit editions of Windows Vista all contain code for using physical memory above 4GB. Microsoft just doesn’t license you to use that code.

Well, to say it that way is perhaps to put words in Microsoft’s mouth. I say the restriction to 4GB is a licensing issue because that’s how Microsoft’s programmers evidently have thought of it. The 4GB limit is retrieved from the registry by calling a function named ZwQueryLicenseValue, which is itself called from an internal procedure which Microsoft’s published symbol files name as MxMemoryLicense. If you remove this check for the licensed memory limit then a restriction to 4GB is demonstrably not enforced by other means. Yet I must admit that I have not found where Microsoft says directly that 32-bit Windows Vista is limited to 4GB only by licensing. The supposed License Agreement doesn’t even mention the word memory. What, really, is going on?

From:
Geoff Chappell, Software Analyst - Viewer

 

[logicearth]

Right, but didn't you notice the OP has only 4 GBs of memory. He/She doesn't need to go above that. Or did I miss something?

 

[y0himba]

Has 4, doesn't show mare than 3.would like to utilize all 4. This explains why the OP cannot see more than 3. Hopefully this article will help explain to the OP what is going on.

Done replying, back on topic.

 

[Antman]

PAE is already enabled by default on Intel Core Processors, it is required to use DEP. However PAE is not for accessing 4 GB, it is for accessing OVER 4 GB. The problem is not 32 bit addressing but hardware address reservations.

+1(x)

 

[H2SO4]

Has 4, doesn't show mare than 3.would like to utilize all 4. This explains why the OP cannot see more than 3. Hopefully this article will help explain to the OP what is going on.

Done replying, back on topic.

A novella-sized programmer-level explanation laced with anti-Microsoft bitterness may not be the ideal way to get the OP started on their journey of understanding.

 

[pscchong]

Gurus, I am only getting 1640MB (1.6G) with 4GB installed in Win 7 32 bit home edition, dual AMD E-350 processor. Task manager reports 2456MB reserved for hardware and available for Windows is only 1640MB ! What went wrong ? BIOS had PAE enable.

 

[GeneO]

PAE is already enabled by default on Intel Core Processors, it is required to use DEP. However PAE is not for accessing 4 GB, it is for accessing OVER 4 GB. The problem is not 32 bit addressing but hardware address reservations.

+1(x)

Actually, if 32 bit windows fully supported PAE for 36bits of address, then then the reserved device memory could be mapped to a virtual address range beyond the physical 4GB of RAM, and the OP might be able to see his full 4GB Intel/MB supported memory remapping for this configuration. That is how it is done in x64 - it would be just like that. (actually I think the device memory is still mapped to virtual addresses under the 4GB, and that section of RAM physical address is mapped to virtual addresses above 4GB).

But that is not the way it is. You are limited to 4GB of virtual address space, and the device Memeory mapped I/O has to be mapped to an address range in that 4GB, which makes it unavailable for the operating system and programs.

 

[GeneO]

Gurus, I am only getting 1640MB (1.6G) with 4GB installed in Win 7 32 bit home edition, dual AMD E-350 processor. Task manager reports 2456MB reserved for hardware and available for Windows is only 1640MB ! What went wrong ? BIOS had PAE enable.

My Computer -> Manage -> Device manager
View -> Resources by Type -> Memory

You should get something like Mine which is attached. Snip it and post it and we can see what is using it

You'll notice that even though I have 8GB of memory in x64 and I have all 8GB usable, hardware is still mapped below 4 GB (on mine you'll see hardware mapped up to FFFFFFFF Hex = 4 GB). The physical memory corresponding to that hole is mapped to virtual address space above 8GB, so is still accessible as I mentioned above.

 

[pscchong]

Many thanks for correcting re PAE (for >4GB). Here is the snip, in 3 files. Noticed that Win 7 Home Basic has not snipping tool. Need to use Snippy for it.

Here are the is it. Look forward for answers to access my memory. (PS this is a Win 7 Chinese version - hence there characters means Memory)