its what software you want to use i see no extra features i would use in 10 over 9.
i stick to stable because i cant aford to take risks.
8GB is fine for video.
see your using the same drive for source and render.
when your rendering do you get 100% usage on all 8 threads in task manager. or near as dam it to 100, if yes you have no issues, if you see it going up and down its a IO issue.
However, even at 47-50% CPU Useage, my temps are still at like 68-72C while rendering.