Re: CRT detection and/or DFP ignore doesn't work longer in newer driver versions
I'm not sure that I fully understand your setup. Are you stating that you have one videocard, and 3 display devices attached to it? If so, this has never been a supported configuration, and if it worked in the past, that was on pure luck on your part. If I'm misunderstanding your setup, please generate and provide an nvidia-bug-report.log which captures the problem.