It shouldnt make any difference, as far as i know there is no dx9 or dx11 versions, its just one format only that they stopped updating at v2.0 in 2014..
Gameguru works with .x as its ptimary import format and automatically converts it to .dbo itself. So its wont make much difference at all.
Primary Desktop:
i7 7700,k NV1070 8GB, 16GB 3200mhz memory, 1x 2TB Hybrid, Win10.
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