I also use daz3 advance for rendering animation which does use OpenGL for rendering and my GPU is 4.2 on a plain-Jane i7 3.0 ghz machine.
Open GL is not a full render and is not ray traced. It’s quality is limited. Even Older versions of Daz3D have an option to render to OGL, and this is really in the same quality levels as rendering out to Poser’s Preview mode in it’s older version, or doing a quick Preview mode or OGL animatic in more advanced 3D software. I think this is where confusion is occouring, in unfamiliarity in the differences in rendering vs Open GL as well as in terminology.
Yes, a faster graphics card will allow faster Open GL Drawing but this will never produce the higher calibre results of ray tracing using even 3Dlight or advanced 3Dlight scripted settings, or firefly medium and high quality, or a full ray tracing application such as Lightwave or the Reality plugin for Daz Studio. The later ones will not benefit from a Graphics Card’s power unless the card and program both support parallel processing (as Reality does, and Lightwave 11 does).
However, if Open GL quality is sufficient, then a good graphics card will definately give a significant performance boost.