Maybe you don't understand what i am saying... In year 2004. if you ware buying R200 card to use radeon driver, and now in year 2014. if you buy current hardware, you will have aproximately same raw performance if you compare Catalyst for Windows against Mesa radeon drivers .
With windumbs, there is no point in time travel because it has HUGE marketshare. So referencing windumbs has only a point as a maximum achievable performance and not as a usable alternatives. Because in that case, thats completely wrong forum.