Can I run a 4GB Video Card in Windows XP 32bit Edition with 8GB System Ram

[saberasus007]

Dear Reader or Responder,

First I want to thank you for your time spent reading/responding to this message.

Here is the situation. I am a very experienced computer user.

I run both Windows 7 Pro 64bit and Windows XP Service Pack 3 32 bit edition (they are on different hot swap drives). I only use Windows XP to run software and games that will not work in Windows 7 64bit. Otherwise Windows XP is not my primary operating system.

The problem deals with memory and the address space XP handles in 32bit. I have always been informed about the memory limitations of a 32bit OS. I currently run 8 GB of memory (RAM) on my motherboard. I am aware that 4GB is the maximum the OS can see and use.

I have decided to replace my EVGA 580 1.5GB video card with a brand new EVGA 770 4GB video card. According to the website for EVGA, Asus, and several other 3rd party board makers and Nvidia (who provides a driver for XP) the 4GB video card will work in Windows 32 bit and 64bit version of the OS. I currently run the Windows XP Home Edition version.

Now I have always known that there is a limitation of XP in how much memory can be addressed. That amount is the approx 4GB of RAM minus the Graphics Card memory. So with a 1.5GB video card, that means you won't be able to have more than ~2.5 GB of memory available to the operating system (before other drivers and software loaded at the start of the OS and then of course programs you run).

I am an experienced user and so this has me baffled and I can not find any tech/support/briefs on the issues of how a 4GB video card can be used in a 32 bit edition OS that can only access 4GB of memory no matter how much memory (RAM) is in the system. With all the companies saying their 4GB card can be used in Windows XP 32bit, I don't see how, since 4GB - 4GB = 0GB, that would mean Windows XP should not be able to run as their is no space left for addressable memory.

Can anyone confirm how a 4GB video card will work in Windows XP Service Pack 3 32bit with 8GB of RAM? Is there some sort of hardware/software/driver/switch/command that disables a portion of the video card memory so Windows XP can run? How or does a 4GB card actually run in Windows XP and more importantly can Windows XP run? I really can use your expert advice and help in resolving this issue.

Just a reminder, XP is on its own hard drive (I used a Hard Drive Swappable Bay, that allows me to run XP and 7 on seperate drives. Xp is only used to run software and yes, no lying, games that will not operate properly in the Windows 7 64bit Pro edition and will not work or needs things that the Windows XP mode for Windows 7 can't provide.

Please help as I have a nice brand new EVGA 4GB 770 FTW video card I bought at an unbeatable price and would love to keep it.

Thanks you once again for your time in reading/responding to this message.

 

[2x4b]

Plug it in and try it. I bet it works great!

 

[Amdlova]

your graphic vram don't count if this is 64bits our 32bits. but 32 bits will recognize only 3.75gb

Due to an architectural decision made long ago, if you have 4GB of physical RAM installed, Windows is only able to report a portion of the physical 4GB of RAM (ranges from ~2.75GB to 3.5GB depending on the devices installed, motherboard's chipset & BIOS).

This behavior is due to "memory mapped IO reservations". Those reservations overlay the physical address space and mask out those physical addresses so that they cannot be used for working memory. This is independent of the OS running on the machine.

Significant chunks of address space below 4GB (the highest address accessible via 32-bit) get reserved for use by system hardware:

BIOS – including ACPI and legacy video support
PCI bus including bridges etc.
PCI Express support will reserve at least 256MB, up to 768MB depending on graphics card installed memory
What this means is a typical system may see between ~256MB and 1GB of address space below 4GB reserved for hardware use that the OS cannot access. Intel chipset specs are pretty good at explaining what address ranges gets reserved by default and in some cases call out that 1.5GB is always reserved and thus inaccessible to Windows.

Buy the graphic card and don't worry Vram is not RAM

 

[smeezekitty]

Some graphics ram will be used as a data window (I think 1 GB)
so your memory limit will be a bit under 3 GB

 

[jimmysmitty]

It will work. As to memory allocation, it will depend as said on a lot of factors.

I am more curios as to what games you have found that run on XP but not on 7. I have a ton of old games and so far they have all worked on 7 and even on 8.

 

[saberasus007]

Starcraft, Diablo, Pacific General, Star Wars Knights of the Old Republic I and II, Homeworld I, Far Cry 1, Uno, No one Lives Forever 1, Force 21, Hellfire for Diablo, Battleground series from Talonsoft, Freedom Force, Close Combat Cross of Iron, Steel panthers world at war. There are others I just haven't had time to try yet. Most of these could not install, couldn't be patched, had color issues in the game, etc. I did all the troubleshooting that I knew about plus I googled each issue to death. As mentioned I am not an inexperienced user, so I tried various reg entries, switches, 3rd party solutions, etc.

I am aware that VRAM is not the same as the OS Ram. However the OS still needs to map the video card memory which is where, based on every tech note, solution, etc. it says that the OS will initially map the memory from the video card to the remaining RAM to determine how much is actually left addressable. That is what concerns me, if it is reserved/mapped, then a 4GB card would take up all the available addressable memory space (in theory). I know that when I use the 1.5 GB Evga 580, all programs that I have run, just to make sure, or validate the information on memory address space reserved for the Graphics card, the list available memory is between 1.75 and 2GB and that is after all the programs that need to run in the background (Norton Internet Security, Graphic Driver, etc).

I haven't had a chance yet to put the card in to see how Windows XP 32bit will show what memory is "technically" available for the OS and software/games/etc. I am not worried of course about Windows 7 64bit (which is why I used the 64 bit versus the 32 bit version of that (win 7) OS).