Consensus on how to get XP to see close to 4GB RAM?

[Speederlander]

I know it won't ever actually get to the 4GB mark, but I also know I can get it higher than the 2.8GB number I am seeing now.

There is so much back and forth info, i.e. (googling a few):
http://www.howtofixcomputers.com/bb/ftopic117376.html
http://www.ocforums.com/showthread.php?p=4705537
http://forums.whirlpool.net.au/forum-replies-archive.cfm/510851.html

Does anyone have some clearcut answers on maximizing the RAM that windows sees? I don't want to just go poking around in the boot file or the registry unless I have some specific and legitimate advice.

Thanks!

[XSAlliN]

I had the same dilema some time back, the answer for me was Win XP ( 64 bit ) or Windows 2003 (actualy on this I could see even 6 GB ) ;)

[GWillakers]

I know it won't ever actually get to the 4GB mark, but I also know I can get it higher than the 2.8GB number I am seeing now.

Does anyone have some clearcut answers on maximizing the RAM that windows sees?

Thanks!

I know I am not answering the exact question you raised...
but I would like to remind you of an alternative that many overlook.

With a 32-bit OS you have a 4 Gig limit... and obviously many things like the graphics card, ethernet are carving claim to a lot of that space.

For the most part, Windows doesn't actually deal with physical memory but virtual. Just parts like the paging system....etc.

Instead of spending hundreds of dollars on a new Operating system, and wrestling with new drivers {complete with their 64-bit glitches},
you could set yourself up a pagefile backed by a Ramdisk.

Consider Gigabyte's GC-RAMDISK.

You could build your system such that it see's 2.8GB from the Motherboard and 4GB of pagefile space, that is backed by RAM and not by disk. This would give you close to 7 GB of usable physical memory.

The last 4 GB of physical memory {resident on the PCI card} would not
be as fast as physical memory accessed by a 64-bit OS. I suppose the SATA interface is the limiting factor. But it is still 150MB/sec. Might one be able to support say 30,000 4-k pages/sec?

I don't know for sure, but would like to see a performance review concerning its ability to support sustained page faults.

[uOpt]

Does anyone have some clearcut answers on maximizing the RAM that windows sees?

Easy. Deinstall SP2.

Before SP2 Windows XP had working PAE. So I have been told, I don't run Windows except on my gaming machine. Win2K should have working PAE, too, so together with (hopefully) working remapping support in the BIOS you get 4 GB. Of course, the 32 bit versions of Linux and FreeBSD have working PAE and see the full 4 GB (might require installing a new kernel).

[uOpt]

With a 32-bit OS you have a 4 Gig limit... and obviously many things like the graphics card, ethernet are carving claim to a lot of that space.


No, there are plenty 8, even 64 GB machine running 32 bit OSes. They just happen to have working PAE in the OS ;)

The limit you think of is virtual memory, which is limited to 3 GB per process on most 32 bit OSes but is 2 GB on some Windows version with some switches and 4 GB-64 KB on Linux with the 4GB/4GB VM split patch (defunct).

[JH_man]

The big question is; do windows also adress gfx card ram etc? And is also the page file included in the 4 GB limit?.. :stick:

JH_man

[uOpt]

The big question is; do windows also adress gfx card ram etc?


The video RAM lives between 3-4 GB physical and is always directly accessible. That is why real RAM living there has to be mapped away (to > 4 GB) by the BIOS to use it. Otherwise it is straight deactivated. (as mentioned, without working PAE you cannot use the RAM after remapping to > 4 GB either so you are just screwed).

If you have 2x 512 MB video RAM cards and a bunch of other PCI junk then you do in fact lose more than 1 GB RAM below 4 GB.



And is also the page file included in the 4 GB limit?.. :stick:


No. Physical memory as defined by RAM+swapspace can be much larger than 3 or 4 GB even in XP "hate PAE" SP2.

I still think it is mind-blowing that every other 32-bit OS can use 4 GB RAM and more just fine, except the one you pay the big bucks for.