The difference between these 3 5970 waterblocks?

[Slipperss]

Is there any performance difference, or is it just the look?

EK 5970 Acetal-Nickel

Acetal

Nickel

 

[rubix_1011]

Yes, most likely just the aesthetic look. The acetal look is more matte/plasticy looking, and the nickel is for the chrome look. The base of the block is most likely identical in each...just a different top.