1/2 RAM AGP aperture makes sense?

[caddmannq]

"Everyone" says to set your AGP aperature at 1/2 the size of your system RAM, but does this always make sense?

What if you have 1/2 GB of RAM? One GB? Does the video really need a half GB of my RAM for caching data?

What programs do you use that really utilize this memory, and what settings do you use for them? The same all the time? Or do you tweak the AGP for best performance with different apps & games.

On my work PC, I often run AutoCAD in 2D mode, and it benefits from a very small AGP aperature (say only 4MB out of 256) , and reserving most of the RAM (252MB) for the system.

On my home PC I tend to allow 64MB out of 512MB for AGP aperature, and my video card has 64 MB onboard. This seems to work fine, but I haven't tried tweaking this PC with different games much.

Anybody done extensive tests or investigation on this one?

[Mntsnow]

I only allow at most 128megs and I see no reason to go higher but then again I dont do alot of gaming?

[Dudster]

I haven't heard the "half your RAM" thing for a long time, everything I've read suggests 128MB as the sweet-spot (for GeForce cards at least) which is what I've been using for a long time (with 256MB and now with 512MB of RAM - and with both 32 and 64MB cards). I think above 128MB it actually gets less efficient (has to store a huge AGP memory table thingy in main RAM) and can cause problems. I think with a few things (like maybe 3DMark), a 256MB aperture can improve performance a tiny bit but 128MB is the best general gaming setting AFAIK.

Also, I think when set below 32MB (or was it 16) AGP gets partially disabled.

[Mythic]

Thats true.... under 16 MB, only 1X AGP is aviable....
Best setting is 128 or 256 if you have a lot of ram.
Othervise stick yo the default of 64MB

[NDC]

To be honest with you, I saw very little difference on any setting for the AGP Aperture in the BIOS. Don't Believe me? Try for yourself setting starting from the lowest value to the highest...

[caddmannq]

I've now tried that on two PCs.

On my work PC, I noticed a degradation of AutoCAD performance (my most important app...could you guess? ;) ) with AGP enabled at all, and eventually set it back to run as PCI, but 4MB was an efficient compromise. (32MB Viper V770 card)

On my home PC, I tested With Serious Sam and Half Life Blue Shift in hi-rez mode. I think there was no difference from 32MB to 128MB with the GF3 Ti500 video card. Also no diff in AutoCAD noticed, but this system has twice the ram & twice the video ram of my work machine (though it's DDR266 & the work PC is DDR333.)

I haven't tested rendering in 3D AutoCAD models, though. I suspect that results may differ a lot. But we never do renderings at work, and 99% of our work is 2D only, so I think it's gonna stay set at 4MB at work.