I think systemlabs must be crazy, you don't need a monster machine to run Rohan, and I remember the HD 3xxx series of radeon already have pixel and vertex shader 4.0
SysLabs is very commonly known to have issues on displaying system properties in relation to software. However, it's one of the better ways (Even with it's flaws) currently to know if you have a chance at playing a specific title. If you don't trust the site, then find another site you trust or make one yourself. The end result is it's best to learn about your own computer before trusting someone else with telling you how good or bad it is. There are far too many computer illiterate people on the internet as a whole. So, that should be incentive enough for you to learn about your machine so you can be a bit more self-reliant.
System Labs only compares your system against the system requirement set by the developer or them self .. there's no actual testing going on when you run their applet. And as we all know, system requirements r never 100% correct.