Downclocking the GPU is really the only way to get power down, I would assume that is their easiest method for reducing power in a console if manufacturing is putting the power higher than anticipated. This is why to a large degree faster memory with the power on the chip and having that speed "off die" vs the esram on die being a huge number of transistors and heat/power all on die making it a much bigger problem.
I would think they could probably find a way to downclock several cores on the CPU but with the clock speed I wouldn't be surprised if both MS/Sony would do that only as a last resort due to the kind of cpu power available and the low clock for the more powerful single threads. Also, look at a "stock" pc with a 80W cpu and 200-250W gpu, in gaming the GPU is more important, would be using the most power and thus is the first to get downclocked to save power.
as for games, Fable 1, great, fable 2 almost carbon copy(I didn't play 1 till after 2, so I didn't realise at first), Fable 3 is god awful, Fable 4.... I dread. Forza, boring, Halo, no where near my favourite game, they'd need some massively better titles to persuade me to buy. Personally I can't see buying either till WAY down the road.
Without checking the whole thread, have people seen the analyst saying the likely cost of the consoles to make is around $275 for PS4 and $325 for the X1, with most of the difference being the kinect, though I'd guess the PS4 controller costs more and the Xbox APU should cost more. They are expecting $349/$399, which I would expect to be about the same in £'s in the end, with a supposed cheaper + subscription model for the X1 as well.
No way these consoles will be £500 and no idea why anyone thinks they might be even close. PS3 had stupid expensive chip, expensive to develop, make and the bluray which cost a bomb 7 years ago, you can basically remove the bluray cost and reduce the chip costs and realise where it would be priced. £300 max, £250 for the PS4 probably, with maybe as low as £200 for a X1 + subscription.... maybe more like £225-250.
