The min shading rate you've set is too low. Try something between 0.1 and 0.5. That combined with a more reasonable bucket size (try 32 for a start) and it should render that scene just fine. The min shading rate tell the renderer how small it should make its micropolygons. 0.5 asks it to make micropolygons that are not bigger than half a pixel, 0.1 says not bigger than a tenth. Luckily there's an internal limit so that 0.0 does not result in an inifinitely small micropoly, but it still causes the render to generate a huge number of micropolygons that consume huge amounts of RAM. The large bucket size in addition asks it to render 10000 pixels (100 times 100) at once, and while trying to cover those 10000 pixels with micropolygons that are only a fraction of a pixel in size, it runs out of memory.