This does not want to be an old and well known topic.

I have 4x OCZ Platinum 6400 800MHz, with the mobo BFG 680i nForce.

Using Windows XP 32bit I reach maximum of 2.75GB of RAM.

I read that this limit may vary depending on your hardware configuration. I saw that you might be able to reach 3.5GB or more?

What hardware do you have that allow you to use more than 3GB of RAM?

I think that I got unlucky with my hardware configuration, because I have one of the lowest (only 2.75GB). Even thought my hardware is not crappy.

(Using Windows XP 64bit I have full 4GB of memory)

Also, do all versions of Windows Vista support 4GB and more? There is any 32bit version of Vista with this limitation?

This is a problem with all 32 bit operating systems. The only way around it is to use a 64 bit OS

http://www.vistaclues.com/reader-q [...] it-windows -vista/

even though this is vista, it will apply to 32-bit xp as well

Thanks for the reply, but your link does not work.

sorry about the link. I tried to re-edit my post and get the link to work but it won't. so try this. go to http://www.vistaclues.com/ and add the extension:

reader-question-maximum-memory-in-32-bit-windows-vista

in the address bar and hit enter. let me know if that works.

Thanks now it is working properly.

Finally reading that article I understood everything I needed.

It looks like if the total supported memory is 4GB then I need to subtract my video card memory 768MB
and I should get something close to the Windows 2.75GB. Even though the subtraction is not really close to what I expected.

4GB (4000MB) - 768MB = 3.2GB (3232MB)

My Windows XP 32bit shoud display 3.2GB, but it displays only 2.75GB. It is fine for me, at least I know that the system is also considering my video memory. ok ok ...

But I am going to buy another videocard with 768MB (2x 768MB = 1536MB) I hope that the windows memory value does not drop to 2GB.

Anyway I am fine like this. To work I use 32bit XP and for gaming I use 64bit XP.

This 32bit limitation is bad, it let me think that we will be forced to switch to 64bit version in order to use more than 4GB of RAM. I think that soon we (gamers) will need to reach 8GB of RAM in order to have high-performace gaming machine. Just think that next year we will have Intel 8 core CPU!!

Indeed, Vista 32 bit should give you same amount as XP 32 bit. Your 8800 gtx has a lot of RAM on it which might explain why you see less available than some others. The OS reserves some of it's 4 gig maximum addressable memory for other things besides your system RAM, such as the video card RAM. I'm a little foggy on the details of exactly how this allocation is done.

ETA ah, just saw your response above. I think the problem is that in addition to the 8800 RAM there are other devices on a system which have addressable memory on them also. When you add them all up you probably end up with what you got.

Yes thanks for your reply. Finally it is becoming everything clear.

But at this point I feel like the 32bit OS (XP or Vista) are old systems that do not support more that 4GB. It is a bad sensation to have such kind of limitations, it is like if Vista 32bit is already old!

And if I want to switch completely to a 64bit OS will have only few compatible drivers and applications. Then I won't be able to run everything.

I guess we just need to wait and have lot of patience until 64bit it will be fully supported.

the 32-bit version of vista is "old" I think microsoft only manufactured it for compatibility issues. Everything should be working toward a 64-bit environment anyways. Microsoft has said that Windows Server 2008 will be the last 32-bit OS that they will make. With the exception of Vista, Microsoft usually offers a new OS every 2-3 years. This means thay by about 2010 we should have the start of an all 64 bit environment.

I see and I really hope that the 64bit era will come soon.

I was trying to install the free Zone Alarm Firewall and it is not suported to run on 64bit. I also tried to install Quake 4 and nothing to do!

At this point we seem to be right on the edge of going to 64 but yet still in a 32 world. For most ppl the small advantage of the extra ram does not outweigh the compatability issues with 64 bit. I say that having never tried 64 bit myself. But on a desktop PC how many situations at this point need more than 2 gig? Even the test Anandtech did which ran supreme commander out of RAM required having an unusual amount of AI opponants. And of courrse many, perhaps most, ppl do get 3.2 to 3.5 gig out of their 4 gig on 32 bit, which ain't so bad. That ought to hold power users who run 32 Vista out of RAM at least for the time being.

Right, I think that for now only few people will need more than 3-4GB of RAM. But I am one of those few people. I think for me the only solution is to keep going with 2 Operating Systems. One 32bit for everyday work applications, and another 64bit for gaming. In this way when I use the computer for work I won't care about the loss of memory. But when I play I will enjoy the full 4GB of RAM.
Even though... 2 Operating Systems costs me double $$!

I have just bought another two gigs of ram and I am running on:
E2160@3.2+Gigabyte P35-DS3P+4x1GB Kingmax 800
Inside windows xp 32 I get 3.5 gigs.
I consider myself lucky. I heard you could get 2.7, 3 or 3,5.

I dont know what games you play that need 4 gigs of ram? Every game I run at 2 gigs runs fine.

There is the off chance that out of 4GB of memory, about 3 -3.5GB could get used in the OS if you're lucky, even if the mobo BIOS detects all 4Gigs. How do I know, coz my previouse hardware supported it. It was an off-the-shealf Compaq Pressario SR1599AN with a ASUS P5LP-LE mobo. I had a look in the Asus site, but this mobo was specifically made by Asus for HP/Compaq so it wasn't available on the retail market, nor mentioned in the Asus website. Even the drivers for this mobo was provided by HP, not Asus. But with my new mobo (EVGA nforce650i Ultra), XP and Vista only see 2.8GB of RAM (Same 6400 DDR2 ram used in the old config), But the BIOS detects all 4GB.

This is strange but my research tells me that if you want to use all 4GB of RAM, a 64bit OS is required (Eg: XP Pro 64bit or Vista 64bit). There is a PAE switch that can be used in the boot.ini file to address the rest of the memory, but this switch only PROPERLY works with Win 2003 32bit OS, so there's really no point in using the switch with XP or Vista anyways.

So I guess if you are not planing to upgrage to a 64bit OS, u may as well sell the extra memory and spend that money on something else.

And no! I've never come accross a game that requires 4GB of RAM. 2GB is plenty of RAM for any game currently in the market.

Cheers!

Open up Windows Task Manager and under Commit Charge look at the Peak value.

I am a gamer and have never seen my computer use more than 2GB of allocation (including what's written to the page file) for any game, even with other stuff running in the background. On this basis I have a 512MB page file and have never had a low or out of memory situation.

2GB is ample and I think people just assume 4GB is going to give them some kind of boost when if fact (1) the system doesn't need more than the 2GB and (2) each application isn't able to use more than 2GB anyway!

Unless you do big video file editing or work with several massive image files at a time, you don't need more than 2GB at the moment in my opinion.