The power draw is nothing though - I did some more measurements with my newish Xeon E3 1230 V2(I had a Xeon E3 1220) and a GTX660 and I still barely see 200W at the wall and the R7 265 is still faster than a GTX750TI and consumes about 30W to 40W more. TPU puts the R7 265 as 16% faster over a bog standard GTX750TI.
The GTX660 power draw is comparable to a R9 270 IIRC.
To put in context at 20 hours a week gaming for 52 weeks constantly,you are seeing an additional £5.61 spent in power consumption at 18P a kWH(for 30W more power consumed).
Plus,you have just ignored entirely what I have posted right??
Civ5 only really used 4 threads and was still bottlenecked by single thread performance.
The Firaxis LORE engine looks like it will be used in Beyond Earth too,so it will probably show similar scaling too.
Look again:
http://techreport.com/r.x/amd-fx-8350/civv-lgv.gif
That is Civ5 late in game. An FX8350 can barely match an IB Core i3 3220.
You want to see another engine which scales like that??
UE3 as used in Thief:
http://media.bestofmicro.com/L/L/427161/original/Thief-Mantle-Mid.png
UE3 scales upto 4 threads and again many of the UE3 based games tend to be limited by single threaded performance.
This is why Mantle makes such a difference for AMD CPUs in the game(and less I would say for BF4 which is reasonably well threaded).
I honestly don't understand why you could not even wait 4 weeks to see how the game does scales,especially since it is an AMD Evolved title.
Almost all the Civ5 reviews are done using Intel CPUs since they are faster for the game.
If I were you I would DSR the card.