Looks like we have two completely contradictory accounts here of what Apple is saying. I thought we had people who have tried the ML beta and seen an improvement?
Also, "some older applications are not efficient with the new GPU" is a cop-out, Apple. If that's true, tell us which ones so we know what to avoid, or know we're going to have trouble if we need to use them. This inspecific blanket nonsense is no use to anyone. That said, I've only been installing software as I need it to avoid having a day where I do nothing else, and I don't think I've got anything particularly old on here. Again, a list, or delineation of how old is "older" would be helpful.
(Yes, I know they don't read these forums; I'm being rhetorical here as well as hoping that someone who's actually in touch with some of these people may point out that a list would be **** handy. Of course, if you're happy to sell hardware that's defective with certain software, or vice versa, I suppose I should not be hoping for much. This approach really is a cop-out on Apple's part and makes me think a great deal less of them.)