XP showing wrong video memory


Sep 19, 2002
Had this problem with previous setup and now reinstalling XP Pro and still have problem.
MSI KT4V M.B. with a Chaintech GeForce2 MX400 64MB video card. When booting up the BIOS reports 64MB video. WinXP is reporting only 32MB (dxdiag). A game of my daughters will not load because it needs 64MB. I have updated the Nvidia drives but XP still only reports 32MB. XP SP1 and SP2 installed and Windows update shows nothing for the video card. Any ideas ?

For it is not what is seen, but what is not seen. :eek:


Update your MSI motherboard drivers.. You can try to change your AGP Aperture size in the BIOS, general rule of thumb is 50% of your RAM. If you have 512Mb in your PC, set aperture to 256.



Dec 31, 2002
Is this the only video card that has been installed in the system or is an upgrade/replacement video car? In either case, remove your video drivers and reboot. You can use a driver cleaner app to ensure the drive is gone, but it's not required. Once you've rebooted from the removal, re-install the driver for your video card.

As for the AGP aperture size, that will not affect how the OS sees the video card. See below:

First of all, AGP Aperture memory will not be used until your video card's on-board memory is running low. That means it will usually not impact your gaming performance because developers are trying hard to not exceed the on-board memory limits.
The bigger your video memory, the smaller your Aperture Size could be. However with later games requiring more and more texture memory a good number seems to be 128MB Aperture Size for all cards with 64 MB to 256 MB Video RAM.
Setting the Aperture Size to HUGE values will not increase performance because this merely sets the maximum amount of physical memory that can be used. It only makes the GART Table bigger because every 4K page has its own entry, no matter if allocated or not.
Setting the Aperture Size to too small values could result in running out of available texture memory especially on a low-mem video card. It is also possible that developers make use of the GART's features by creating textures as 'non-local'.

If you experience in-game stuttering try playing with the size of your Aperture.

What is it from a technical point of view?

When using an AGP card the video memory on the graphics adapter is mapped into the 4 GB memory address space (above the region of the physical installed memory). Any accesses to this memory region are directly forwarded to the video memory, greatly increasing transfer rates. However in earlier days of video cards graphics memory was rather limited and ran out quickly (a single 32-bit 512x512 MIP-mapped texture consumes ~1.5 MB) so AGP added a mechanism to use the system's main memory as additional storage for graphics data such as textures. This is what the AGP Aperture is. Usually directly below the mapped video memory the system reserves a contiguous space of addresses the size of your Aperture (no physical memory will be consumed at this time).
When free video RAM is running low the system dynamically allocates 4K sized pages of system memory for use as AGP Aperture Memory. The problem with this dynamic allocation is that in many cases the pages are spread in a non-contiguous form throughout the physical memory. Accessing these pages directly would hinder performance because of scattering/gathering requiring extra logic. To get around this limitation the GART (Graphics Address Remapping Table) which is implemented in hardware in the Northbridge's Memory Controller Hub provides an automatic physical-to-physical mapping between the scattered pages and the AGP Aperture.

The actual usable amount of this 'virtual' AGP memory is less than half the AGP Aperture size set in the BIOS. This is because the Aperture is divided into two areas. One uncached half and another write-combined area.

Summary: There is no "right" size setting, rather there are wrong ones. The 128 setting is a good starting point for video cards with 64-128 mb video ram, and from there it's just tweaking for whatever software you are running.

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Jan 27, 2005
SOme MSI Mobos have particular memslot layouts that insist memory is in specific slots. I got my MSI mobo in a compaq X box where the ram was installed right next to each other. POST read the 1gb DDR400 128bit as 512 DDR300 64bit and XP read it as the same until I read the manual and moved them to the appropriate slot then it read correctly.

Sorry I re read my post and it has nothing to do with your problem at all. Where is my medication....<P ID="edit"><FONT SIZE=-1><EM>Edited by palmerg on 04/29/05 07:32 PM.</EM></FONT></P>

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