Back in 1999 when the Quake source code came out, I started working on "Quake 2000" which was an improvement on the rendering pipeline of the code. I ended up getting free cards ship to me - one was a GeForce256, one was the Matrox G400 DualHead and I think the other was the ATI Rage 128 Pro.
The GeForce blew the other cards performance out the water. The Matrox was particularly bad and the dual screen didn't add much and I remember maybe 2 games that supported it.