I am looking to get an AMD 7770.

According to litecoin.info, these are the types of 7770s tested.....

http://i.imgur.com/BsfXOmp.png

first column is Mhs, 2nd is core clock, 3rd is memory clock...

But when I look for this item on websites like scan.co.uk, I get the following

http://i.imgur.com/mscNiTP.png

As you can see, memory clock is 4500 Mhz.....

I don't get it.... Why is memory clock 4500 Mhz...?? All the ones on litecoin.info show between 1125 and 1425 memory clock... 4500 Mhz is vastly more..??

What is going on here..