The Xbox 1 or one?

Sure they can! At-least in some respects anyway.
For example, compute performance is directly tied into how many Shader Pipelines and the chips respective clockspeed, considering everyone on this forum *loves* to measure things in flops... You would only need an extra 400mhz on the GPU core clock to match the PS4's GPU compute performance. I.E. 1.2ghz core clock which is *not* impossible for a GCN architecture.

However, they would most certainly require additional voltages for that kind of boost, I wasn't an engineer for Microsoft's Xbox, so I'm not aware of the TDP headroom they designed the Xbox One's cooling system around, so in that regard I have NFI.

it would be more relevant longer, instead of needing to replace it in 5 years it would be better future proofed as far as consoles go. They need to at least get closer to their competition. it will be interesting though, if they did up the ram and clock speed, which i think is a good thing, would they charge more or eat the costs? or maybe a pro edtion?

You are forgetting that the Xbox One uses a one chip apu design. If it were an external card then yes maybe they could achieve those speeds. With the gpu sharing the same space as the cpu? Sorry but no way, not if it was not designed for it from the start. Also it would still be lacking somewhat in the memory bandwidth department.

If they want to increase clock on anything they should increase it on the cpu instead.

Nah, you can achieve that in an APU, I've overclocked AMD APU's beyond 1ghz on the GPU core and they were all VLIW4 based.
Great thing AMD did when they implemented the Resonant clock mesh and power gating.

Also, Memory bandwidth is only half the story, these are consoles remember, you aren't gaming at super high resolutions.

Why do that when teh power of teh cell kloudz already gives it infinity RAM?

Cloud is slower than Ram, higher latency than flash memory. :P
They would be better off using the Hard Drive to make "Virtual Ram". Aka. Like in Windows. :P

@Permalite

Its not impossible but how are the yields for that clockrate ? Can they even produce millions of 1200mhz gcn gpus (for a reasonable cost) ? I think 1 ghz is somewhat realistic. Given the size of the box I think it can handle the additional heat. But still I doubt MS is going to do that anyway.

http://www.eurogamer.net/articles/digitalfoundry-in-theory-can-xbox-one-cloud-transform-gaming

^ That was the article I read about it, but I guess a better place to look is here:

This kind of stuff.  By saying the console is "three times more powerful" because of 'the cloud', they're not only saying that they're offsetting the power advantage but actually pulling it in their favour.  Or at least how I understand it in laymans terms?

So if this happens will this preserve the "the most powerful console never wins the generation" pattern? Or is PS4 still going to be more powerful over all?