Graphics card not recognised?

[leisurechest]

I keep getting a warning that "Best graphics card detected on your system has less than 512 MB of video RAM."
So I have to use very low settings. But I have an Intel Iris card with 1.5 GB. Seems it's just not recognising it for some reason?

So far this is happening with The Witcher 2 and Tomb Raider.
I'm using the latest edition of the 13" rMBP. With the graphics card mentioned, as well as 2.8GHz i7 processor and 16GB RAM, I feel like I should be getting a much better result.

Haven't got anything helpful from Googling so far. Anyone come up against this and/or solved it?