Cannot get my BenQ XL2420TE above 60Hz over DVI-D with Windows 8

[dm3565]

I'm running Windows 8, with an Asus 7970 DCU II and a dual monitor setup: a Dell U2413 (main display) and a BenQ XL2420TE, both connected over DVI-D. Both monitors properly identify, but I cannot set the XL2420TE to any refresh rate above 60Hz. Any suggestions?

 

[Superjoe]

Is your cabling dual-link DVI-D, or just DVI-D?

http://twobrotherscoatings.co.uk/wp-content/themes/dvi-dual-link-6919.jpg

 

[dm3565]

It was dual-link, but I tried a single link cable, and it produced the same results.

Edit: Ah, need a dual-link cable for anything other than 60Hz... I'm a doofus.

 

[dowant120hz]

amd cards only have 1 dual-link dvi
one of them is limited to single-link