Folks, I am making some slight modifications to a logo I did with minimal camera moves. I notice that it used to render in a scanning fashion (top to bottom) and fairly quickly. Now the same project file loaded in 2.42a renders slower and in blocky chunks.
Simple man now the makers of blender have used the xparts and yparts have both been changed to 4 so it renders automatically without you setting it. Oh yeah this is the wrong forum but I’ll still help you out in your dilema.
First on the buttons window you click on the render button near the bottom you can see the x and y parts and change them to 1 and you get the old default render for 2.41.
Though changing the x and y parts makes it faster try looking at your computer to see if it has enough memory. It may not so delete your useless stuff.
I think it might be to help the threading. If you have a dual CPU, you can hit the threads button to use both processors but if the render isn’t split then it’s probably harder to use both processors effectively. I’ve seen Blender render more than one of these buckets at once when threads was turned on.
I think it uses less ram too if you’re rendering in parts.