hey! I've also got a dell precision m4800, for which I purchased and exp gdc beast expresscard version, everything is working fine with my gtx 970, although I think I can't use my internal display with it, how did you get it to work with internal display? the stuff you've said doesn't really make much sense to me, any help is appreciated thanks.
Here is your laptop's download page. I suggest you try and install Dell's own AMD Firepro driver first to see if it works or not: -us/product-support/product/precision-m4800-workstation/drivers
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