On my i7 4GHz 4 cores/8 threads running on an iMac, Christmas lights scene was rendered in 2'40".

Record broken ! 2'26" [:))]

Core i7-4790 - RAM 16 Go - GC : GeForce GTX770 2 Go (Dx12) on PC

But without knowing the initial conditions... [X-(]

Here are mine:
a christmas tree posed as outside on a textured floor and a textured sky.
A photo rendering (800x600 in Q4) as showed on the picture ...


Is it this ?