Thanks for the responce guys. I did alot of searching and reading of articles about the effects of AGP aperature size settings, following are my conclusions:
1. AGP Aperature Size (AAS) is MOBO sys memory that your Graphics card will use when the graphics card onboard mem is all used.
2. AAS setting was much more important in the earler days of graphics cards when they only had 16/32M ram on the cards. With todays 128/256M cards this setting is not as important.
3. You can set the AAS in the bios, but alot of the box pushers (emachines, gateway, compaq, dell, hp, ect...) are leaving the advanced graphics setting out of their modified stripped down bios. In these cases the AAS is usually hard set to 32 or 64 or 128M and cannot be changed.
4. If your bios does allow you to set the AAS this is how it works. That AAS mem you set is not used by the graphics card (GC) unless all the onbard mem on the GC is used up first. The actual amont of addidional mem that the GC gets is only a percentage of the size you set your AAS too, this is because there are gart tables and mem wasted for administrative tasks that support the AAS feature. The formula is AAS/2 -12M. So if your AAS is set at 64M your GC is only getting an additiona 20M of ram (but remember in the days of 16/32M GC's this was significant. if the AAS is set at 128M you are getting an additional 52M, AAS set at 256M you are getting an additional 116M. bellybutton set to 32M you are only getting an additional 4M. The sys mem (AAS) is not used untill all the GC on card mem is used, so other apps and proccesses on you pc can use the AAS sys ram untill the GC needs it.
5. If you can adjust your AAS in the bios never set it lower then 16M, if you do the AAS feature is diabled, and some programs may not run if they expect AAS support, even if you have a GC with 256M memory do not set the AAS to lower then 16M.
6. Now for the myths and rummors, i did alot of google searching and found many recomendations for setting the size of the ASS, the two most common were:
(1) Set your AAS to half your sys ram:
Does not make sence for todays PC's with with greater then 512M sys ram. If you have a PC with 512M or less ram, and a GC with 64M or less ram then following this rule may be good advice.
But if you have a GC with 128/256M ram then there is no need to raise your AAS (leave it at the default 64 or 128M setting).
(2) Set your AAS to the size of the mem on you GC:
This is what the nvidia install guides states, but does it really matter or make sence to do this. With that amount of mem on the GC's they probably won't need additional mem space, and remeber you are actually getting less then 50% of the AAS setting (AAS/2-12M).
Actually setting the AAS to these higher settings 128 or 256M can actually slow things down because the mem GART tables will need to be larger.
So here are my conclusions:
For todays generation of GC's with 128/256M of mem on the card AAS is not nearly as important as it was in the past with the older 16/32/64M mem cards. If your bios does allow you to change it set the AAS to 64 or 128M. If your bios does not allow you to modify it thats fine, the 32 or 64 or 128M default that your bios is using will be fine with GC's with 128/256M of ram.