I don't have any links to prove it, but yeah, fishmahn has it right. The performance isn't any different. The difference is in the power used and heat generated. Of course there probably aren't links to articles proving it because it's one of those things that really doesn't need proving. If it's the same core running at the same speed then it'll have the same performance. The voltage isn't going to cause that to be any different.
The LV and ULV use less voltage, thereby producing less wattage of heat, and thusly run cooler and save battery life.
That's pretty much their only point, but it is a good one to those who care. In theory they'd make better overclockers too, but since they cost more than a standard voltage version, that kind of defeats the purpose of saving money by OCing. Heh heh.
So anywho, in theory you could underclock a regular CPU. In practice it won't gain you nearly as much if you don't also undervolt it. Even then you'll probably never get the power/heat down to being as efficient as a LV, and definately not likely to get down to ULV levels. Efficiency from ground up is a lot easier than the other way around.
But if you're looking to save battery life on a laptop then look at your monitor backlighting levels. Backlighting is generally a big power eater. Turn it down and you'll save a lot of juice.
For that matter speakers can be hogs too. Using those ultra-small really-low-voltage earbud headphones instead of the built in speakers (and turning down the volume as well) can save a bit of power as well.
The only problem with low voltage headphones on computers is that many computer sound systems pick up a lot of low level noise from the PC that you might never hear with speakers or normal headphones but you can hear all too well with low-voltage headphones. :\ On my work PC I can even clearly hear the signal noise from hard drive access as a high-pitched squeal if there's no sound playing and I crank up the volume. Come to think of it, I have to try that on my home PC sometime and see if it's any better...
<pre><b><font color=red>"Build a man a fire and he's warm for the rest of the evening.
Set a man on fire and he's warm for the rest of his life." - Steve Taylor</font color=red></b></pre><p>