I am sorry to hear you are having this problem but let me help you.
Please access the following link since this information has been provided there already:
Thank you so much for answering promptly. I'm afraid however the discussion you referred me to didn't quite clear things for me. As I mentioned above i have tried changing the BIOS settings for DMVT, but under all of them, including the Maximum (which was actually the default) the Dedicated VRAM is still 64mb. I thought maybe it said 64 but then it allocated more memory as necessary, but the game keeps crashing so that doesn't seem to be happening. I apologise for maybe not being totally clear earlier, but my main question is why changing the BIOS isn't altering the VRAM when i see it has worked for other people with similar issues, as in the discussion you presented. Could this maybe be a BIOS issue that could be solved with a BIOS update? Terribly sorry if the answer is quite obvious and I'm just being daft. Thank you for your patience.
The dedicated memory can be changed at the bios level but this depends on the OEM manufacture limitations/decisions.
The VRAM is the same as Video memory or it is also known as dedicated memory so as mentioned before, the options depend on the computer manufacture.
You can try a bios update but the bios updates usually are created to fix known issues in the computers. I would recommend you contacting the computer manufacture for them to confirm if it is possible to increase the dedicated memory.