The FLEX card has more electonic circuitry so it can run multiple monitors (Eyefinity) without needing to use a Displayport adapter.
http://www.sapphiretech.com/presentation/product/?cid=1&gid=3&sgid=1041&pid=1099&psn=&lid=1&leg=0
You see to run three screens with a single ATI card, one of the screens must have a Dispalyport input (rare) or you need to use a "Active" Displayport port adapter to convert the graphics card displayport output to DVI,
http://www.sapphiretech.com/presentation/product/?cid=4&gid=1010&sgid=1011&pid=357&psn=&lid=1&leg=0
These two 6950 cards will be better for you if Eyefinity isnt any interest,
http://www.overclockers.co.uk/showproduct.php?prodid=GX-036-HS&groupid=701&catid=56&subcat=1752
http://www.overclockers.co.uk/showproduct.php?prodid=GX-128-MS&groupid=701&catid=56&subcat=1752
http://www.sapphiretech.com/presentation/product/?cid=1&gid=3&sgid=1041&pid=1099&psn=&lid=1&leg=0
You see to run three screens with a single ATI card, one of the screens must have a Dispalyport input (rare) or you need to use a "Active" Displayport port adapter to convert the graphics card displayport output to DVI,
http://www.sapphiretech.com/presentation/product/?cid=4&gid=1010&sgid=1011&pid=357&psn=&lid=1&leg=0
These two 6950 cards will be better for you if Eyefinity isnt any interest,
http://www.overclockers.co.uk/showproduct.php?prodid=GX-036-HS&groupid=701&catid=56&subcat=1752
http://www.overclockers.co.uk/showproduct.php?prodid=GX-128-MS&groupid=701&catid=56&subcat=1752

