For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.
Dell M5950 card with a modified VBIOS. With these cards it is not the GPU at fault it is a strange power issue that I have not found the solution to.
Get an M5950 card and ask me for the VBIOS in private.