I have a Dell Precision M6500 with a Firepro M7820 in it, that was upgraded to Windows 10 a month or two before I received it. I am trying to find drivers for Windows 10 for the card. I saw that there were some beta drivers but even those don't appear to be available for this Firepro card. Windows 10 doesn't show up as an option for this card when I manually choose it under the normal drivers or beta.
The current driver works fine for gaming but things like the brightness adjustment on the screen don't work. I'm not even sure what driver is currently installed since the card shows as a Radeon HD 5800M in the device manager.
Do you know that it is a kind of bug in system that window is not showing daily driver updates/driver update news. But you can also manually update drivers in Windows 10 by below given steps. I hope this might be useful to you. In case if this will not give you desired result then switch to Dell Precision M6500 Manual for another recommendations: