How to set up two graphics cards

[WarCannibal]

Hi Tom,

I have two ATI HD3870 video cards, both have 512 of ram, and my system originally can with Vista. As soon as Win 7 came out I installed Win 7 and got the latest and recommended video drivers for my graphic cards.

When I run a diagnostic on the cards it tells me that One of the cards is a master card and the othe is a slave. I am supposed to be running at 1GB GPU speed, however when I run more benchmarking tests, It tells me that I only have 512 ram installed?

I recently found this out the hard way when I tried to run Battlefield 3, Can you please tell me how I can get these cards to run together.

Thanks for your help in advance!

Regards

John

 

[Helltech]

When you have two cards in CF (or SLI), the RAM doesn't not get added together like that. You are only supposed to have 512mb of effective ram.

 

[kajabla]

^yep. Xfire and SLI use both sets of RAM, but it comes out to the same amount.
http://www.youtube.com/watch?v=BlXlczDEAXs

 

[WarCannibal]

Best answer selected by WarCannibal.

 

[WarCannibal]

Thanks Guys , is there any way to get the cards to run at 1GB GPU speed? and if it possible, will I get better performance? Thanks in advance!