Displacement mapping is still really not that supported in HW... IMO only card that has it is Matrox, and those are far behind in speed when compared to the more popular cards ppl use for gaming. HW disp mapping links:
http://users.belgacom.net/gc610902/technical.htm
http://www.pcstats.com/articleview.cfm?articleid=1109&page=5
http://www.matrox.com/mga/products/tech_info/pdfs/parhelia/displ_mpg.pdf
http://users.belgacom.net/gc610902/technical.htm
http://www.pcstats.com/articleview.cfm?articleid=1109&page=5
http://www.matrox.com/mga/products/tech_info/pdfs/parhelia/displ_mpg.pdf