First off, a big thank-you to Nic for showing interest in fixing the driver. I believe it's not pointless to be excited about some real progress anymore.
So far, I've found 2 freeware games in my library that have a flickering problem, Driving Speed 2 and the Driving Speed Pro demo. When Specular Bloom is enabled, there is a ridiculous amount of flickering all over the screen, even if no 3D rendering is being done. Also, whether or not bloom is turned on, there is flickering when any 3D rendering is being done outside of a race, i.e. when displaying car models in "Career Mode - Home". In Driving Speed 2, any transition where the screen fades to black (like when you click Options) is accompanied by a brief period of flickering. This doesn't happen in DSP.
In Source engine games, there is a lot of flickering, but that can be fixed by turning on V-Sync. That decreases performance, though, so I really don't like doing it.