And why does then the original Surface Pro work with my two Samsung TVs? Just the 3 Pro doesnt. Different graphics chipset/drivers?
I forget which model Series 7 you have. I did some checking this morning and found things like:
http://www.samsung.com/us/support/owners/product/UN55HU7200FXZA April 2015 firmware
http://www.samsung.com/uk/support/model/UE55HU7200UXXU May 2015 firmware
So I'm definitely interested in what model you have, what firmware and if there is any newer firmware available.