http://bugs.winehq.org/show_bug.cgi?id=35847
--- Comment #5 from DL dredgingthelake@gmail.com --- Okay, I've written a patch for the 690, 780M, 780TI, and Titan. However, there seems to be VRAM related problem. The 780M has a memory size of 4096MB whereas my card (780) has a memory size of 3072 MB.
So I force enable the 780M using it's pci ID with VideoPCIDeviceID registry entry to test the patch. As a consequence, I get out of memory errors. Fair enough, perhaps its trying to use more memory then my actual hardware has.
Here's the thing, if I force enable the PCI id for the Titan there are no memory errors, despite the Titan having 6144 MB. If I then edit my patch to give the Titan entry a VRAM size of 4096, the same problem occurs. Alternatively, if I edit the 780M entry to use 6144, it starts working again.
My theory is that Wine is ignoring VRAM sizes greater than a certain size, and that is the explanation for not getting out of memory errors with 6144 MB of ram.
Anyway, I've attached the patch to see if I'm not completely off base or if I' ve made an obvious error.