Vista only sees 2.75 GB of my 4 GB of RAM

I installed Vista RC1 on my new computer but it only sees 2.75 GB of the 4 GB of RAM installed.

I've read some hosh posh google searches here and there about PAE, or some PCI BIOS settings, and other craziness, but I can't figure out how, if it's even possible, to get Windows to see all 4 GB.

Anyone have an idea?

Originally I ordered 2 x's 1 GB sticks. The only real reason I ordered 2 more sticks is because my MOBO manual states that it has boosted performance when using 4 sticks of RAM.

But now I'm thinking I'm actually taking a performance hit by going over the 2 GB mark. At least if I'm reading these articles correctly. It seems that anything above 2 GB in the 32 bit world has to use some kind of virtual address translation or something that taxes the CPU.

So I can easily still return the 4 x's 1 GB sticks.

Would 4 x's 512 MB be ok? I'm just thinking that 2 GB's is just barely cutting it these days. At least for the amount of Multi Tasking I do. I'm wondering if I get 3 GB of RAM, if I'll still have problems.... I'm thinking yes.

I don't remember building PC's being this much of a pain in the in the past.......

If I could just get Windows to see the full 4 GB. I could do some RAM test at 4 GB and then take out 2 sticks and test with just 2 GB and see if there is really a difference.

Oh yeah. My motherboard is a SuperMicro X7DAE with 2 x's 5130 Woodcrest Xeons.

I've not been able to get any 32 bit version of Windows to show a full 4GB of RAM. The closest I've come is with Windows 2003 Server which shows 3.5GB. I've also tried adding boot.ini switches like /PAE, /3GB, etc.... I think you need to move to a 64 bit version to really get the most out more then 3GB of ram but I could be wrong.

That's what I was afraid of. Why do they even say that Windows supports 4 GB if it really doesn't?

Makes no sense. And then. Since I'm seeing 2.75 GB, is it just using 3 sticks of RAM, leaving the 4th cold? Very confusing, and very frustrating. I'd hate to have to return this RAM to Newegg. I'll end up taking a $110 restocking fee.

I guess what it boils down to is this.

I already have the 4 x's 1 GB sticks.

If I return 2 of the sticks. I'll be left with 2 x 1 GB sticks. Supposedly, for best performance, the mobo recommends using 4 sticks of RAM.

So if I return all 4 sticks, and then buy 4 x's 512 MB sticks. I'll have 4 sticks for a total of 2 GB, but it will actually cost MORE than what I already have, because of the restocking fee.

So should I just take the hit, keep the 4 sticks I have and be happy with my 2.75 GB of RAM?

You need a 64bit OS to make use of all your memory.

If you need the cash, return two 1gb sticks and keep the others, don't bother with 4x 512, you may be able to / want to run 4gb in the future.

Windows does technically see 4GB of ram, but it does run out of address space. The most my dual Opteron machine ever had available in Windows was 2.5GB of ram out of 5GB of memory.

One of the 64bit versions of Vista or Windows XP Professional x64 Edition will see all of that fine without issue. You can use PAE mode to do it, but the performance hit makes it worthless in my opinion for most applications. I'd go ahead and leave it there, sucking up 1.25GB of ram. That way you get your boost from having 4 sticks installed, and you don't use PAE mode. You probably don't need more than 2GB available for your machine in Windows anyway, and if you do I'd suggest a 64bit OS instead.

The thing that still doesn't click for me, is that when you search Microsoft's support site for info on PAE, every article relates to using memory ABOVE 4 gig.

Is it possible that Windows only sees a MAX of 4 GB of RAM, so it's taking into consideration my physical RAM + Page File? When I get home, I'll try messing with the page file and see if that makes any difference.

jimmarch said:

The thing that still doesn't click for me, is that when you search Microsoft's support site for info on PAE, every article relates to using memory ABOVE 4 gig.

Is it possible that Windows only sees a MAX of 4 GB of RAM, so it's taking into consideration my physical RAM + Page File? When I get home, I'll try messing with the page file and see if that makes any difference.

Click to expand...

No. Windows will only see up to 4GB of ram, but that isn't Windows fault exactly. It is a limitation of a processor operating in 32bit mode. 4GB is the limit of 32bit memory address space. As far as the page file, it should be seperate entirely. A page file larger than 4GB would get broken into multiple 4GB paging files and addressed virtually. A 2GB file limit exists within 32bit Windows as well. Further compounding the problem.

Disabling your page file will not help. I have tried that in the past when I had 5GB of ram.

Windows does not have a 2GB file limit, either for the page file or for any user file. (Unless you're running FAT16, in which case the partition size is limited to two gigs -- and I hope you'll be able to upgrade soon.) FAT32 has a 4GB-1 limit.

The limit for a page file is four gigs on Win32. A page file of four gigs doesn't get split, and isn't "addressed virtually", whatever that possibly means.

Windows can see more than 4 gigs of RAM directly if you're using the appropriate version of the operating system. Windows XP isn't such a version.

mikeblas said:

Windows does not have a 2GB file limit, either for the page file or for any user file. (Unless you're running FAT16, in which case the partition size is limited to two gigs -- and I hope you'll be able to upgrade soon.) FAT32 has a 4GB-1 limit.

The limit for a page file is four gigs on Win32. A page file of four gigs doesn't get split, and isn't "addressed virtually", whatever that possibly means.

Windows can see more than 4 gigs of RAM directly if you're using the appropriate version of the operating system. Windows XP isn't such a version.

Click to expand...

I wasn't referring to Windows XP Professional x64 Edition which does not have the limits I speak of. 4GB is the max physical memory Windows XP 32bit can work with that doesn't involve work arounds. I miss-spoke about the page file. 4GB is it's limit. I was referring to the 2GB process limit. Windows XP Professional x64 Edition doesn't suffer from any of those limitations. Windows XP 32bit does.

http://support.microsoft.com/?kbid=237740

http://download.microsoft.com/downl...a909-fbba470af276/Benefits_of_Windows_x64.doc

The last link has a document that has all the information concerning the 2GB limit per process in Windows XP 32bit.

It states that there is a 2GB per process limit in Windows XP 32bit unless you are using the 3GB switch in the boot.ini.

Dan_D said:

It states that there is a 2GB per process limit in Windows XP 32bit unless you are using the 3GB switch in the boot.ini.

Click to expand...

This much is true, though you'll also need to have the programs you're running marked to be large address aware.