It does require a computer that can run games like GTA 4, Crysis on high etc
Having a video card with 1+ GB memory helps a lot.
There are certain console commands you can enter to turn settings down, like
"r_pr_shadowdetail #"
The default is 4 (which I think is some what to high) Try setting that to either 1 or 2.
"r_pr_maxlightpasses #"
Default is 5, You could try make this number lower as well, but then you will notice a lot less lights.
Further more, you will find all the discussion on Polymer and EDuke32 in this thread as it has moved from 3DR a long time ago to here now.
http://forums.duke4.net/index.php?showforum=26