The next two games are famous for being memory intensive, so perhaps our half gig card will fare better here.  The first of these is Quake 4.  Based on the Doom 3 OpenGL engine, Quake 4 provides some excellent graphics and detail.  Id Software caps frame rates to 60 fps during gameplay hence the spikes on our graph never really go over that.  Settings here were "High" with 4x FSAA at 1024 resolution on the MCC Landing Site level.

More of the same.  As you can see in the graph, things went well until one section where the action heated up making gameplay less than enjoyable for a few seconds as things dropped all the way down to 16 fps.  We attempted to make a second run under the "Ultra" settings but no matter what we did, the settings would not hold once we restarted the game. 

Next up is Doom 3.  Same engine, same game developer but fragging zombies is just plain fun so it's here.  Settings were "High" at 1024 resolution on Site 3: Analysis Facility level.  Again, you can see the 60 fps gameplay cap courtesy of Id Software.

The 6600 based card, irregardless of how much memory on it gave good gameplay but struggled to keep up with the 6600 GT based card.  Adjustment of the settings to the "Ultra" mode did appear to stick with Doom 3, so using the same level we repeated things but at "Ultra" high settings.

Our results under "Ultra" were very similar as they were under the "High" setting.  So much so that I believe the game is scaling back its settings so as to not overwhelm our mid range cards.