I have a nice brand new dell gx280 with 4gigs of memory.  Windows xp will only see 3 gigs of it.  is there anyway I can get the os to see all of it?  Is it possible that even if the os doesn't see it that an application can still take advantage of all 4 gigs or memory?

First make sure that all the memory is recognized in the BIOS, then make sure your mo-bo´s max limit of ram. Also check your mo-bo´s manual about installing 4gb ram, might be something like on one I had.

My manual said:

"Note: due to standard PC architecture, a certain amount of memory is reserved for system usage, and therefor the actual memory size is less than the stated amount.
For example, 4GB of memory size will instead be shown as 3.xxGB memory during system startup."

 

Could also be CPU related.

If none of this gets you anywhere I´d call Dell Support.

ah.....the ole 4gb maximum Windows memory requirements.

Well, unfortunately...it may have to do with the fact that Windows can only see 4gb of ram period...system ram, and virtual ram.  Since you have 4096 of system ram, and your pagefile is on...you've passed the Windows memory limits.  Remember, Windows sees the pagefile as system memory.

The only solution you could try to get Windows to see all of your ram, would be to shut off the pagefile.

For those of you using Windows Server 2003, the mem limit:  32 bit - 32Gb...64 bit - 64Gb.  Seeing as only a few dual CPU motherboards even come close to this, offering support up to 20Gb of ram....W2003 has no issues with the requirements.

Also take note, that with 4 x 1 gig memory modules, the latency (clock cycle time) is slower than 512mb modules.  Your system would perform faster with 4x512mb (2gig), than 4x1gb (4gig).

unfortunately this system is built for code compiling and simulations. Thus the memory requirment. 

and yest the bios sees the memory just fine.

 

Starjax

The only two options I see, is to either install Windows 2003, which can be configured as a workstation, or try turning the pagefile off.  If programs fail to run with no pagefile, I'd recommend going to W2003.

To configure 2003 as a workstation (as you have XP), check THIS SITE.

thanks.  We turned the pagefile off and that seemed to resolve the issue. 

Even though you have solved it, there is some good information here...

http://support.microsoft.com/default.aspx?scid=kb;en-us;308417

we're having the same issue here on two systems. the manual for the board states that if we're using 4 1gb modules that the system will only show 3.xx.  POST shows 4gb of RAM but windows shows EXACTLY 3GB of RAM. we've turned off the paging file and that has done nothing for us (still shows 3GB of RAM)

 

any suggestions?      

Windows xp will not see more than 3gigs of physical ram.  If you upgrade to xp64 then you are able to address up to 12gigs of ram.  (please take into account the above posts)

If you install Windows 2003 Server SP1, it will fix your problem.  You will be able to see 4GB of memory in windows.

the manual for the board states that if we're using 4 1gb modules that the system will only show 3.xx.

Check for BIOS updates to those boards.  If the board itself is limited, you may be forced to pull one mod from each board, as they are not being used by the system.

Is this true?  If Im running XP and gaming with 4 gigs RAM (4 x 1 gig memory modules (PC2-4200 (DDR2-533)), my machine will not perform as fast as it would if I had 2 gigs RAM (4 x 512MB) because of the latency?

If so, is there anything I can do to correct this?  I just spent $480 bucks on 4 gigs of memory...

 

Thanks!

 

As far as benchmarks go, you'd see some performance hits....but for most games, you probably won't.

The os is the only way.

 

So, windows xp is not fully utilizing the 4GB memory? If it is not, then I have to remove 1GB DIMM out and resell it

Please correct me if I am wrong.