what is AGP aperture in bios?

**travistee** · January 7th, 2006, 12:27 AM

I have an asus9200se with xp.
Its 8x agp. 128K.

The bios has a default of 64K for the AGP
aperture ( I think thats what it says).

How do I decide what to use.
64k, 128k ?

**theonetruely** · January 7th, 2006, 03:04 AM

Originally Posted by travistee

I have an asus9200se with xp.
Its 8x agp. 128K.

The bios has a default of 64K for the AGP
aperture ( I think thats what it says).

How do I decide what to use.
64k, 128k ?

hi travistree
i normaly set A.G.P aparture to half the amount of RAM i have
hope that helps you

**confus-ed** · January 7th, 2006, 05:15 AM

AGP aperture == GART size (the two phrases aren't quite the same as ones an allocation & ones the thing that might use that allocation, & a 'GART' is a Graphics Address Remapping Table ).

Here's a quote where somebody explains it very nicely ..

..AGP aperture does two things. It selects the size of the AGP aperture and it determines the size of the GART (Graphics Address Relocation Table).

The aperture is a portion of the PCI memory address range that is dedicated for use as AGP memory address space while the GART is a translation table that translates AGP memory addresses into actual memory addresses which are often fragmented. The GART allows the graphics card to see the memory region available to it as a contiguous piece of memory range.

Host cycles that hit the aperture range are forwarded to the AGP bus without need for translation. The aperture size also determines the maximum amount of system memory that can be allocated to the AGP graphics card for texture storage.

Please note that the AGP aperture is merely address space, not actual physical memory in use. Although it is very common to hear people recommending that the AGP aperture size should be half the size of system memory, that is wrong!

The requirement for AGP memory space shrinks as the graphics card's local memory increases in size. This is because the graphics card will have more local memory to dedicate to texture storage. So, if you upgrade to a graphics card with more memory, you shouldn't be "deceived" into thinking that you will need even more AGP memory! On the contrary, a smaller AGP memory space will be required.

It is recommended that you keep the AGP aperture around 64MB to 128MB in size, even if your graphics card has a lot of onboard memory. This allows flexibility in the event that you actually need extra memory for texture storage. It will also keep the GART (Graphics Address Relocation Table) within a reasonable size.

To get the 'ideal value' for your systems you'd have to do some benchmarking, but generally now I just leave it at whatever value bios has as default, unless I'm trying to create a 'screamer' for my customer & need every single setting at its possible optimium ..