How much of a difference between these cards?

[coldest]

http://www.newegg.com/Product/Product.aspx?Item=N82E16814127566
OC version $180 before MIR, $163 after MIR

vs

http://www.newegg.com/Product/Product.aspx?Item=N82E16814127576
Non OC version, $160 before MIR, $125 after MIR

I think I am stuck with MSI because my case only have about 10 to 11 inches of clearance for the card. and this card is only 8.5 inches. Or if possible, someone suggest another brand that might fit into my case. and i am powering this card with a antec earthwatt 430

Or i think i can get this too
http://www.newegg.com/Product/Product.aspx?Item=N82E16814150516
this XFX branded one is 9.25 inches at 165 before MIR and 135 after MIR

vs

http://www.newegg.com/Product/Product.aspx?Item=N82E16814150573
same price as above



which brand should I get and which card out of that brand should I get

 

[we1shcake]

go for the cheap one and overclock it to the levels of the higher one, same performance less money, although if you can afford it a 6870 should fit and that has better performance

 

[coldest]

Get the XFX HD6870 it's only USD169 before MIR
10% more performance for just 10buck more

it's 20 bucks more, but i am considering it as well

 

[coldest]

Best answer selected by coldest.