Installed Ram Shows 4GB and it says 2.5GB are usable - Page 3

**mailman2** · 04-27-10, 09:39 PM

Quote:

Originally Posted by mojoman0

lol I think this guy is getting way too much info. Install Windows 7 64 bit and you will be set!

+1, just install Win7 x64.

**Rakeesh** · 05-08-10, 12:55 AM

Only one of two solutions work for you. One, as everybody has already stated, use 64-bit windows. Two, use physical address extension (PAE.) Note that PAE is less CPU efficient when it comes memory addressing.

The problem is this: 32-bit kernels can only address 2^32 bytes of memory, or 4GB. The easiest way I can think of to describe that problem in plain English is to compare memory addressing to a table of contents in a book. Suppose that the page numbers in a table of contents could only be two digits long. This means that the table of contents can't refer to, or "address" any page above 99. Let's also suppose that this same book has 120 pages, and you can't turn to any page that isn't addressed by the table of contents. This means that the extra 20 pages you have are useless.

Does that make sense? Now in a computer, anything that is memory takes up physical address space in this "table of contents." This includes your RAM (that "4GB of memory" number you throw around) your motherboards BIOS, your video card, and any memory on any PCI cards you might be using, etc. It all adds up to above 4GB. Your main "memory" goes last in this address space, e.g. it is what is at the end of the table of contents no matter what. So the actual memory that you can use is your 4GB minus everything else. Hence, you can't use all 4GB. How much you can actually use depends on what other components you have.

Physical Address Extension is basically saying instead of one table of contents, we can have two or more in additional volumes that are in the same book. Everything past page 99 goes into volume 2, and the page numbers start all over again. It takes more CPU operations per memory operation to do this however, thus it's slower to do it this way.

If we take this analogy from 32-bit to 64-bit, then we double the number of pages that the table of contents can address. So instead of a maximum of 99 pages, we can go up to 9999 pages.

Make sense?

Chuttyfanta · 04-25-12, 02:33 AM

I also face same problem. I bought 8gb RAM i7 64bit windows7 home premium but that time, only 2.95 GB ram . Now I upgraded to Windows7 enterprise 32bit , still 2.95 only usable. How can I maximise my RAM.

Dr.Nick · 04-25-12, 11:39 AM

Hi, welcome to the forum. Before you do this I do recommend you switch to a 64bit version of the OS. There really is no reason not to these days and your 32bit key should work fine on the same version x64. The following should do the trick for you if you insist on it

http://msdn.microsoft.com/en-us/libr...8VS.85%29.aspx

**XDanger** · 04-26-12, 01:40 PM

Quote:

Originally Posted by Chuttyfanta

I also face same problem. I bought 8gb RAM i7 64bit windows7 home premium but that time, only 2.95 GB ram . Now I upgraded to Windows7 enterprise 32bit , still 2.95 only usable. How can I maximise my RAM.

You were lied to, It was 32 bit windows 7. Unless you mean it showed 2.95gb free in Task Manager?

**mailman2** · 05-01-12, 10:08 AM

Quote:

Originally Posted by Chuttyfanta

I also face same problem. I bought 8gb RAM i7 64bit windows7 home premium but that time, only 2.95 GB ram . Now I upgraded to Windows7 enterprise 32bit , still 2.95 only usable. How can I maximise my RAM.

Either...
1 its 32-bit Windows
2 your motherboard / or bios doesn't support more ram (check for bios update)
3 (in some cases, I don't believe in yours) onboard GPU will use some

05-08-10, 12:55 AM	#26
Rakeesh Join Date: Jun 2004 Location: Sonoran Desert Posts: 6,853	Re: Installed Ram Shows 4GB and it says 2.5GB are usable Only one of two solutions work for you. One, as everybody has already stated, use 64-bit windows. Two, use physical address extension (PAE.) Note that PAE is less CPU efficient when it comes memory addressing. The problem is this: 32-bit kernels can only address 2^32 bytes of memory, or 4GB. The easiest way I can think of to describe that problem in plain English is to compare memory addressing to a table of contents in a book. Suppose that the page numbers in a table of contents could only be two digits long. This means that the table of contents can't refer to, or "address" any page above 99. Let's also suppose that this same book has 120 pages, and you can't turn to any page that isn't addressed by the table of contents. This means that the extra 20 pages you have are useless. Does that make sense? Now in a computer, anything that is memory takes up physical address space in this "table of contents." This includes your RAM (that "4GB of memory" number you throw around) your motherboards BIOS, your video card, and any memory on any PCI cards you might be using, etc. It all adds up to above 4GB. Your main "memory" goes last in this address space, e.g. it is what is at the end of the table of contents no matter what. So the actual memory that you can use is your 4GB minus everything else. Hence, you can't use all 4GB. How much you can actually use depends on what other components you have. Physical Address Extension is basically saying instead of one table of contents, we can have two or more in additional volumes that are in the same book. Everything past page 99 goes into volume 2, and the page numbers start all over again. It takes more CPU operations per memory operation to do this however, thus it's slower to do it this way. If we take this analogy from 32-bit to 64-bit, then we double the number of pages that the table of contents can address. So instead of a maximum of 99 pages, we can go up to 9999 pages. Make sense? __________________ Want to listen to audio without your computer going to sleep? Try this. Core i7 2600k 4.4Ghz 1.385v \| Corsair H60 \| 8GB Corsair Vengeance 1600 8-8-8-24 \| MSI P67A-G45 \| OCZ Vertex 3 \| Sapphire 7850 OC to Max settings

04-25-12, 02:33 AM	#27
Chuttyfanta Registered User Join Date: Apr 2012 Posts: 1	Re: Installed Ram Shows 4GB and it says 2.5GB are usable I also face same problem. I bought 8gb RAM i7 64bit windows7 home premium but that time, only 2.95 GB ram . Now I upgraded to Windows7 enterprise 32bit , still 2.95 only usable. How can I maximise my RAM.

04-25-12, 11:39 AM	#28
Dr.Nick Registered User Join Date: Nov 2004 Posts: 1,044	Re: Installed Ram Shows 4GB and it says 2.5GB are usable Hi, welcome to the forum. Before you do this I do recommend you switch to a 64bit version of the OS. There really is no reason not to these days and your 32bit key should work fine on the same version x64. The following should do the trick for you if you insist on it http://msdn.microsoft.com/en-us/libr...8VS.85%29.aspx __________________ i7 920@4.03\|asus p6t7ws\|6gb ocz\|gtx580oc sli\|x-fi fatality\|x25m+12tb\|enermax 1kw\|dell u3011 & 2405fpw