did using the dvi-d fix this issue? I am having the same problem
Wow Wth I cant believe ppl are still replying to this thread, I fixed my issue several months ago.
I believe at the time, because displayport was so new to me, that it didnt register to me till later that my monitor had a display port connection, so now Im just using a high speed minidp to Dp cable, and yes I get 120hz refresh rate with that.
None of the combos I tried with the minidp to dvi adapter worked btw.
Another option, that apparently just became recently available is a high speed minidp to hdmi cable, these were off the market for some time but recently became available again.