which card?

[tn_joeysome]

my dell e310 just has pci slots, so im limited down to 3 new video cards. would anyone tell me which of the 3 is best? they are:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814129062
http://www.newegg.com/Product/Product.aspx?Item=N82E16814103031
http://www.newegg.com/Product/Product.aspx?Item=N82E16814129069
thanks

 

[MoMo1988]

The X1550. most powerful pci card

 

[tn_joeysome]

ok, but what does it mean when it says "memory clock" because the other two have 533 MHz and the X1550 has 520 MHz?