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AGP Aperture Size - Does it really matter?

A setting that everyone can play with that could change your life, as long as you live for your framerate

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Image credit: Eurogamer

If you ever dip into your PC's BIOS, you'll now doubt have spotted an obscure little variable tucked in there labelled "AGP Aperture". The default seems to be that it is set to 64Mb, half the main system memory in most cases. In fact, many hardware vendors and journalists have given long-winded arguments in favour of setting it to half your total system memory, or thereabouts. But in reality, does it really matter? "Many individuals have expressed concerns as to what Graphics Aperture Sizes should be implemented within the BIOS to achieve maximum performance," or so says this detailed forum posting over at According to their data, "there is no perceivable difference when varying the Graphics Aperture Size". They even have a graph to prove this point. So what's the be all and end all on the subject? Well apparently, "Doubling your AGP memory size, adds 12MB for virtual addressing. The doubled amount is for write combining. If you specify too little, you will get paging to hard disk, and you may get errors if you specify too much." As the author says, there is very little definitive information available on the subject, leading to a lot of idle speculation (from whence the "half your total system memory" argument originated). Obviously this setting is very graphics card dependant, which in all honesty just adds difficulty to the equation. For the benefit of those of you who just want to do and be done, we recommend you leave it alone unless you have concrete information one way or the other. Adjusting the variable seems to give application-dependant improvements, so the way you change the setting is entirely dependant on which applications you use regularly and how they perform at each level. Research, I'm afraid, that really needs to be carried out invidually. As such, it's somewhat difficult to be conclusive.

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