I think the trend we're seeing, for both the CPUs and GPUs, is to minimize the amount of power at idle and when performing minimal tasks. That's great in terms of improving battery life. Your octocore laptop will draw the power of a netbook when you're surfing static web pages or doing word processing.
It also means that, when on battery power alone (and on AC power alone), that octocore laptop will have the max performance of perhaps a dual-core laptop.
But when you're on AC power AND you have a fully-charged battery, then you'll have full octocore power (just as many current ThinkPads only achieve full performance when they can draw power from both sources). But you'll only be able to achieve that performance if the cooling system can dissipate all of the resulting heat. That's where the question mark is right now, particularly with the Calpella quad-core processors in 15" laptops. And with the higher-clocked 128-core 3800M in the W701.
You can run the fans at full RPM earlier and more often. But you still have to deal with the steady-state condition of the CPU/GPU running at full speed for a sustained period of time, while playing 3D games for example. And if you can't dissipate that heat, then you'll have to throttle back the processors, meaning that you won't be able to take advantage of their full performance.
So that may mean that you've just wasted the extra money you spent on the extra-20%-faster processor, for example.
Like you say, neither of us knows at this point whether the W510, for example, can handle the fastest processors that Lenovo offers for it. Or whether the W701 can handle the fastest processors Lenovo will offer for it. And I've seen reviews where people say their 15" quad-core laptop runs cool, but then they've never tried to push it's performance limits for any sustained period of time. So they have no idea of how much heat it pumps out in those conditions. The quad-core processor is not all that useful or cost-effective, if all you're going to do is word processing and light web-surfing.
Actually, by the time octocore mobile processors come out, they'll be using smaller chip design rules, so their circuits will be smaller and they'll have better performance per Watt. Another trend we're just starting to see is offloading of processing power, even for video games, to the cloud. So you may subscribe to a supplementary online computing service, to which you'll hand off a complicated piece of code that you want executed simultaneously on 256 high-speed processors. You'll get the result back in few seconds, which will make your netbook look like a super-computer.
Well, actually, your netbook won't even look like a netbook. It'll instead be a thin piece of plastic that you carry around in your pocket and unfold on the table in front of you. Or it will be mounted on your sunglasses, and will project its display directly into your eyes.
And that isn't too far off. We'll wonder why we wasted our time with those big clunky netbooks and iPads. (In your 60-something haze you'll wonder, iPad... was that the name of a computer, or was that a feminine hygiene product?)
BTW, I see that the W701 is now apparently available at www.lenovo.es
. It's listed in a fixed configuration with only 2 GB Memoria.