Created attachment 127280 [details]
sr3 flush.png

Performance is quite poor, while the gpu load is very low. The attached
screenshot shows that gpu load is proportional to fps, and their pattern is the
opposite of the amount of flushes. In typical scenes fps can barely reach 30
while gpu load is around 40% and cpu load is at 60% all the time. I turned off
all special effects for this screenshot to show that this only depends on the
scene complexity. In fact turning on all the effects don't affect performance
much, because the gpu and the cpu are barely loaded.