I've got a AMD Radeon HD 6990 and I keep getting a mention that I need to update the drivers to 23.3.2, but the newest update I could install is 15.200.1062.1004 (Catalyst 15.7.1) / Win10 64. I've tried to install stuff like the adrenalin 23.3.2 software, but that didn't work. So can someone please help!
That is a very old card they don't make new drivers for it, I guess just ignore the update driver notices. Or try these modded drivers https://www.amernimezone.com/
It isn't listed in the compatibility section of https://www.amernimezone.com/ . So are you sure it would work?
Oh wait. Is it this one? https://sourceforge.net/projects/amernimezone/files/Release%20Legacy%20Terascale%20%28Pre-GCN%29/
I'm not sure, I've never used them but yes that card is Terascale.
There is a dedicated thread on guru3d forum, they will probably be able to answer your queries on the software.