Video cards have NO affect on rendering times. Rendering is CPU dependant.
The test result is the total time, in seconds, spent during the test calculating renderings.
I assume that very short times (like 0.6 you reported) come from computers with no PhotoView license for the test to run.
There are two questions here:
1) A score of under 1 is not valid, we will investigate what is happening here.
2) This version of the performance test does not push the graphics card. The first version was focused on CPU and disk performance tests. We would like to better test/differentiate graphics cards and need to find a way to provide valid tests and will work, or handle, card that have advanced capabilities while still allowing lower end cards to be tested and separate these cards from the workstation grade graphics cards. We are looking into how to provide meaningful numbers.
I have also explained more about the test in the post https://forum.solidworks.com/community/administration/hardware_and_os/blog/2011/01/04/solidworks-performance-test.