If they did go as large as they could on the interposer, however, that would also raise questions.
Following the assumption that you want each stack aligned with the GPU, and following the picture that has as little margin as possible, the math gets weird in the absence of implementation details like how much area is lost to spacing requirements or any components.
Let's just say being flanked by HBM takes a rounded up 12mm off of one dimension of a GPU mounted on a big, say 26x32mm interposer.
The other dimension of a 14 x ~32 or ~26 x 20 area is the length that the 7.3mm long HBM stacks plus some margin can fit into. If it were not significantly shorter in that dimension as well, it would seem a little bare.
Following the assumption that you want each stack aligned with the GPU, and following the picture that has as little margin as possible, the math gets weird in the absence of implementation details like how much area is lost to spacing requirements or any components.
Let's just say being flanked by HBM takes a rounded up 12mm off of one dimension of a GPU mounted on a big, say 26x32mm interposer.
The other dimension of a 14 x ~32 or ~26 x 20 area is the length that the 7.3mm long HBM stacks plus some margin can fit into. If it were not significantly shorter in that dimension as well, it would seem a little bare.