Good question
We know that the Surface PRO can run Black Ink quiet well ( which use an Intel HD 4400 ).
From What I read the Intel Iris technology has a Intel HD 6100 GPU and it's quiet good GPU from this
marks. However by best advice is to test Black Ink ( if possible ) on such device before taking a decision If you want this device to mainly use Black Ink.
Perhaps some users has already used Black Ink on such device and share with us their experience.