Scope: This post will explain AGP Aperture Size, and how to adjust it. Properly adjusting your AGP Aperture Size will likely cure may texture-related crashes like the Flaming Arrow CTD (Crash To Desktop).

Short answer: For most RTW gamers, the BIOS setting should be 128 MB. Most of you that are getting CTDs will find you currently have it set to 64MB or less and/or are using a low-memory AGP Card.

HOW to change BIOS settings

You need to make some setting changes in your motherboard BIOS. If you don't know what BIOS is (It is an acronym for Basic Input/Output System), but like to play games on PCs, then take some advice... learn (google or visit your MB/computer maker website, or read the manual in the BIOS section). Learning just very basic things about the BIOS will help you greatly for years to come!

Where is BIOS? When your machine boots, one of the first things it does is look for a video card about 2 seconds after power on. Then the machine begins to initialize BIOS, and during a short period of time (varies by maker), you can press a key to interrupt this process, and enter the BIOS setup.

Setting your BIOS: The AGP Aperture Size

Note: There following are some generic steps (look at your own motherboard manual for exact info!!):

1. Power on the computer (boot it).
2. One to two seconds after the message about the video card at the top or top right of the screen, press the DELETE key. Some machines want you to press the F1 key, and some others like Compaqs, expect you to press F2 or F10. A few want F11 or INSERT.

NOTE: Most machines will, by default, display a quick message like "Press F1 to enter BIOS". If there is no message, and you don't know how to enter your particluar motherboard's BIOS, then Google (search) for it. Or you can do trial and error... Boot, begin pressing DEL about once per second after video initialization, and if the machine does not enter BIOS setup, then reboot and try one of the other keys I suggested.

3. The first BIOS setup page is typically about IDE drive configurations. The second page, usually called something like "Advanced", is where most makers put the AGP Aperture Size setting.
4. Find a reference to something like "AGP Aperture Size"; note what it currently is, then change it to 128MB.
5. Typically the last tab (or screen) is the BIOS Setup exit/save screen. Go to it, and "Exit Saving Changes" or "Save and Exit" or something similar.
6. The machine should reboot.

Remember, this is a generic procedure... there is NO SUBSTITUTE for getting a .PDF or hardcopy manual of your own motherboard, and reading about your own, specific BIOS. Adjusting AGP Aperture size is not hard, but take your time and be both careful and deliberate when making BIOS changes. Do not get sidetracked and be tempted to start changing ANYTHING else! Only change this one, single thing... then play and test your machine thoroughly for stability in gameplay. Then reread your manual and google some more if you get adventurous and want to change some other things that you might have discovered along the way.

Explanation of AGP Aperture Size (not required reading)

The memory on your graphics card (if it is AGP) is mapped into the region of the physical installed memory called the 4 GB memory address space. When your computer accesses this memory, requests are directly forwarded to the video memory, which increases memory transfer rates greatly. In the first years of the AGP video cards, video RAM was small (16MB or 32MB typically), and a single texture could take 2 MB. So a work-around was invented, and that is AGP Aperture. However, potential issues can arise as a result. For instance, when the video card RAM gets low, additional memory is paged (mapped) into various locations of physical RAM. In effect, it is scattered about, which causes certain other issues. So a thing called the GART (Graphics Address Remapping Table) was invented (it runs in your motherboard Northbridge, BTW) to take care of the mapping issues. Many of you might have heard or seen the GART driver being installed in your system updates.

So how does this help you tweak your AGP Aperture setting?

1. AGP Aperture memory is not used until your video card's on-board memory is low (e.g., full of textures), and since developers like TCA do not want to cripple your game experience, they try not to exceed the capacity of your card memory.
2. Generally, the greater your video card memory, the smaller your Aperture Size needs to be.
3. In reality, 3D games need lots of texture memory!
4. 128MB Aperture Size seems to work well for most cards with 64 MB to 256 MB Video RAM.
5. Using a 256 or greater Aperture Size will not increase performance because (as some of you are already guessing) it merely sets the physical addressing of physical memory that can be used. Further, excessive AGP Aperture sizees will only make the GART Table larger, since every memory page has its own address entry, whetehr actually allocated/used or not.
6. Setting the AGP Aperture to too small can easily result in running out of available texture memory... particularly with a 64MB or less video card.

So if you have followed this discussion so far (forgive my glossing over a lot of tech stuff to simplify), the light may now come on why flaming arrows can cause crashes... the flame (and not just flames for arrows!) are textures, and textures eat memory, and you need them all at the same time, and your graphic card is out of memory to store textures, and now the AGP Aperture mapped memory (your system RAM) is used since TCA could not keep to the limit, and now that memory is full when your flaming archers cut loose, and now there is a situation that the program and the operating system cannot resolve, and now the game is terminated to maintain system integrity (you got a CTD!). Bang.

Oh, and now some of you are doubtless seeing actual reasons for some of the system requriements, and a few are probably realizing that you can get away with shaving some requirements... most of the time ("Oh, I run RTW just fine with my pathetic XYZ video card"). But there can be times when you hit the wall. This post happens to explain one of the situations how and why (by inference) some people might be able to use sub-par hardware with tweaking (e.g., trial and error) of this single BIOS setting.

Here are some guidelines for AGP Aperture Size:

Your system RAM is less than 192MB: Set AGP Aperture Size to 64MB.
Your system RAM is 256MB or more: Set AGP Aperture Size to 128MB.

Note: Higher AGP Aperture Sizes can make your GART table swell in size and hurt performance, or even CTD in some 3D games with certain hardware combinations.

Happy hunting now that your flaming pigs and arrows can be loosed ...

PS, there are many BIOS setttings, and this is just the tip of the iceberg. Fortunately, RTW gamers can avoid most headaches by having good hardware, properly configured, properly updated (drivers and BIOS), properly installed.