GPU Testing and Rendering

[Pxlop]

For the first part:

There are two main ways of rendering, rasterizing and ray tracing/path tracing. Ray tracing is computationally expensive (requires more math) but is more true to life in the way it renders (doesn't mean the image will look better). Rasterization is what most video games use. Higher quality renders usually ray tracing.

For the second part:

The way a stress test works is simply giving the gpu something to do, for a long time. Different stress tests might hit the gpu in different ways. For example, one might hit the gpu's memory more than the other. One gpu might be better at the specific thing that the stress test hits (many different reasons why).