Under Tools > Options > Document Properties > Image Quality there are a couple of sliders you can change to increase the image quality.
There is a reason SolidWorks specifies minimum requirements for computer hardware and a list of approved graphic cards for use with SolidWorks.
You are using/testing video cards that where introduced in 2005/2006 and where entry level, low cost video cards in their day. They are very outdated and under-powered by today's standards. Not surprised they no longer support the hardware with up to date drivers. http://en.wikipedia.org/wiki/R520
I am pretty confident today's onboard video GPU's will outdo those video cards of old.