AGP Aperture Size


I am currently running a semi-old computer: a 3GHz Pentium 4 on an Asus P4C800-E with an AGP expansion slot. It has 4GB of PC3200 DDR, a 500GB hard drive, and a BFG GeForce 7800 GC 265MB videocard on the AGP slot.

I’m getting ready to upgrade to a newer AGP card: the HIS Radeon 4670 1GB, to be exact. What size should I set my AGP aperture to? I know the basic concept behind the tech—the aperture sets the maximum size of system memory that can be used for an additional frame buffer by the videocard. So if I’m moving to a card with more GDDR, should I set the aperture smaller or larger?

—Bill Walker

Bill, in the Olden Days, AGP aperture let you use system resources for video memory if you were running out of videocard RAM, and the common advice was to set your aperture size to half your available system memory.

Newer videocards, however, have much more memory than earlier models. With 1GB of GDDR on your new card, you should be fine with an aperture of 64MB to 128MB. You might want to try running 3DMark with varying aperture sizes to see where your system performs best. It could be as low as 16MB; it probably won’t be higher than 64MB.

We should mention, however, that most of our editors advise against spending any more money on an AGP system. We’d suggest saving the $130 or so that that card will run you and putting it toward a new machine; $600 will build a significantly faster rig.

SUBMIT YOUR QUESTION Are flames shooting out of the back of your rig? First, grab a fire extinguisher and douse the flames. Once the pyrotechnic display has fizzled, email the doctor at for advice on how to solve your technological woes.


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