Currently I have a gigabyte p55a-ud3 motherboard (crossfire ready) with 1 9800gtx card installed. I have an older 6600 gt card and am wondering if I can install it for memory support. Would this technically still require SLI technology?
What are you trying to accomplish? the 9800gtx won't be able to use the memory of the 6600gt. Even SLI, which requires basically identical cards, won't add the memory of the two cards together. I don't even think you could use the 6600gt for Physix.
It might be possible to use it to support more than two monitors, two on the 9800 and one on the 6600..