September 24, 2002

The following write up on changing the AGP Aperture setting was provided by Tony. This write up originally appeared on the Yahoo Discussion Forum. Thank you, Tony, for letting my publish your write up on this site.

The AGP Aperture is the amount of system RAM which the ATI Mobility M1 GPU can use for additional graphics texture memory. There is a setting in most desktop and some notebook bioses which allows this to be altered. Sony, in their infinite wisdom, does not make this available in any of the available bioses for our laptops.

The AGP aperture, in the standard 128Mb shipped Vaios, is set to 64Mb, in the 256Mb shipped models it should be 128Mb. In both cases the AGP aperture is set to 1/2 of system RAM. Adding additional RAM will NOT by itself change the aperture, ie. an FX210 with 256Mb system RAM will still have an aperture of 64Mb, not 128Mb.

However, if a bios upgrade has been performed AFTER installing the RAM, then the new bios will alter the aperture based on the amount of system RAM available at the time of flashing. In this case, an FX210 with 256Mb installed which is then flashed will now have an aperture of 128Mb. Likewise, those of you with 512Mb RAM should have an aperture of 256Mb.

There is no way to alter this from the bios, however I have come up with a way to do this from Windows. The following has been tested on my FX210 with A4 1.0, 256Mb RAM and works in both XP and WinME. This solution should also work on the FXA and European AMD based Vaios as well.

You wil need three small downloads:

1. WPCREDIT

2. WPCRSET

3. KT133 Plugin for WPCREDIT

I suggest you get these from http://www.viahardware.com and while there please read their instructions on how to use it and how to apply the KT133 patch. Brad also has links to this in the "FAQ" section of his site.

WPCREDIT allows some changes in the chipset and bios, such as memory timings etc. WPCRSET is necessary to maintain the settings after each reboot.

To change the AGP aperture, run WPCREDIT and find the address "84", or "80-04" on the grid. If you have successfully applied the KT133 patch you should see "Graphics Aperture Size" referred to in the right pane. 

From here you need to manually edit the binary (Bin) or Hexadecimal (Hex) to the amount of system RAM you wish to allocate to the aperture. The available settings are as follows:

Once you've edited it, be sure to save the settings in WPCRSET to maintain the settings each time you boot.

You can check your aperture in both WCPUID and PowerStrip. Sandra does not seem to report the aperture correctly for some reason. I set mine to 32Mb and ran the graphics config utility that ships with Nascar 2002, and it reported "32Mb fast texture RAM" available.

There is no one "definitive" setting for the aperture. Some say it should be 1/2 of system RAM, some 1/4. Just find what seems to work best. I've tried all the settings available, and found that 32Mb or
sometimes 64Mb works best with my 256Mb installed RAM. Yes, smaller seems to work better!

Be warned: This is only a small tweak and will not turn your Mobility into a GeForce4 Go or a Radeon Mobility! At worst you won't notice any difference, at best you may notice a "smoother" frame rate
or a decrease in "jerky" rendering. 

-Tony