Expect "leaked" benchmarks at end of November/beginning December.
As for £350, what planet are you on. The new GT300 is so much more than a gaming card that it will cost to have one.
Personally I expect 10 to 30% faster than 5870 for £400 to £450 and all ATI will do then is drop the price of the 5870 to £250, the 5870X2 to £400 and ATI will still claim the faster "single" card again.
And as for power levels all the stuff I read I read from there "launch" the other day would suggest it being a bigger power hog than the GTX285. Time to buy those 1000W psu lads if you want two in SLI or a GT300GX2.
Personally I hope they release it sooner so I can bag two 5850 for £300 or even a 5850x2.
I'm not even sure by the end of November they'll be able to tell where they can place final clocks, so they take a huge amount of risk releasing numbers then, if they go to low at clocks they know they can get but not what they were hoping for, it might simply get spanked, if they go too high, and then can't achieve those clocks by the real release, either delay it further, or release with less performance than they said it would have, either way it looks incredibly bad.
AS for power, I'm sure it will use more, almost everyone has said so, however, we're only talking, 200-225w being the likely ballpark under full silly load, with 90% of real usage being well below that, likewise a couple won't be using more than 500w, probably closer to 400W under crap like furmark, and 350-380 under heavy gaming, which isn't anything to bad, and nothing a 600-700W psu can't handle with ease.
THe problem is a launch, without availability won't push ATi prices down, a token £10 drop just to say look we can drop prices and they can't even get stock in at the higher price no one wants to pay, to laugh at them really. But large competitive price drops are unlikely till Nvidia have stock everywhere, which is months away
But Nvidia can do what they did on the 260gtx, simply make no profit to continue sales, so they can sell cheap, but as a business, long term its a horrible plan and thats all they've been doing for a year. Hence 777million turnover, and 38million profit, which means with R&D they'll be at a loss, thats excluding the payoff's they've made over dud gpu's over the past year.
Long term they don't have the strength AMD had to stay in debt, nor now the deep deep deep deep deep pockets AMD have that make debt almost irrelevant.
Going to be very interesting, looks like 5770 will be out and about today, final specs will be interesting, could be a great great budget card that blows anything Nvidia have out the water. Why by a 260/275gtx, when a 5770 costs the same, is faster and will only get faster with newer games. Only spec not really known is how many ROP's it lost from the 5870 to get working parts, anything over 16 and it could be a killer, killer card for £130, two in crossfire might bring us 4770 crossfire joy, IE 5870 performance, or even more, for £260.