9800 gtx+ sli setup. PC only sees 512mb instead of 1g?

For some reason, my computer is only detecting 512mb of video instead of 1024mb from running 2 9800 GTX+ video cards.

My computer came with 2 8800GT video cards in SLI configuration. It had a SLI Bridge connector which was connecting both of the cards. The 8800GT configuration looked like this:

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the "||" represents the SLI bridge connector. As you see there is only one place on the 8800gt card where I can place the bridge connector

Here is what my 9800GTX+s look like on the top

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as you can see, there are 2 possible spots to connect my sli bridge. Currently, the bridge that came with my 8800Gt cards is now placed like this:

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The periods are just placeholders for the "||". no spaces allowed i guess

My computer does detect that there are 2 video cards on the motherboard. I used Nividias ntune app to increase fan speed of each card and both show that they are seated properly in the pci-e slots

anyone know what's wrong? I have the most recent drivers. my 8800 Gt cards came in my pc in sli configuration already so i know my computer supports sli.

I'm running windows media center (32 bit xp) with 4G ram, and 3.6GHZ quad core processor

i really have no idea what you said but when i had both 8800GTs hooked up in sli, i saw 512mb of video total. each card was 256mb each. Shouldn't i now be seeing 1G?

During gameplay, each card has to rely on its own memory, it can't use the other card's memory. It would be WAY too slow if that's how it worked.

Here's a quote from www.slizone.com (i.e. nvidia's official SLI site)
"The graphics memory is NOT doubled in SLI mode. If you have two 128MB graphics cards, you do NOT have an effective 256MB. Most of the games operate in AFR (alternate frame rendering). The first card renders one full frame and then the next card renders the next frame and so on. If you picture SLI working in this way it is easy to see that each frame only has 128MB of memory to work with."

As for your other cards, either they had to have been 512 MB cards, the tool you were looking at was wrong, or the system was just marketed as having 512 MB. Multiple graphics card rendering absolutely cannot combine the RAM of each card being used.

http://www.slizone.com/object/slizone_ask_mmm013.html
http://www.gtaforums.com/index.php?showtopic=394615
http://www.hardforum.com/showthread.php?t=1059999