Could you please let us know the driver version you are running? Please go to Device Manger> Display adapters> Intel(R) HD Graphics right click on Properties and then go to Driver, you will be able to see the version installed.
Driver version is 220.127.116.1131.
I bought another cable, this time white Belkin 1,5 m MiniDisplayPort to MiniDisplayPort cable. It seems this was a cable problem, since most of the things seem to work ok now with 60 hz refresh rate. There are at least one peculiarity, Thunderbird right hand upper corner seem like this:
MiniDisplayPort to DisplayPort cable did not work.
Thank for sharing your outcome.
What version of Thunderbird are you running?
Have you tried reinstalling it?