head over to www.xbitlabs.com to see the latest quad sli review (posted yesterday). The review shows that quad sli is unable to run certain games in certain settings. Hopefully a new driver will fix this problem soon. Head on over there and check it out for yourself.
i was in a hurry to post the thread but ive had a quick look through the results and i don't care if you're bill gates there is no way that the performance, or lack of it, can justify the cost of quad sli as it sometimes scores lower than an x1900xtx cf and even worse at the higher resolutions, 2560x1600. you'd get more joy from simply burning your money.
The edit tabs there for a reason, any way, good link. They are realy expensive and dont realy make up to the cost. 2 cards is enough for me at the moment.