For all its qualities the 1640 couldn't do without decent performance, but this is never a problem for it. Its 2.53GHz CPU happily chomps through most things you could throw at it. Unless you're very demanding we can't see many people being unhappy with the performance, though the option for a quad-core processor might just have tempted prospective photography buffs even further.
Battery life isn't terrible, either, though it'll be interesting to see how it stacks up against the 17in MacBook Pro, which Apple claims can last for up to eight hours thanks to its hybrid nVidia 9400M integrated graphics. Indeed, it's curious that Dell hasn't opted for this in the 1640, especially since its 13.3in little brother does. In any case, in the Productivity segment of MobileMark 2007, the Dell managed two hours and 22 minutes, with the lower intensity Reader test ending in two hours and 42 minutes. Neither of these are bad results for such a large notebook and you could get a little more with some optimisation.
As for gaming, the ATI Mobility Radeon 3670 and its 512MB dedicated memory do a decent job. In Trackmania Nations, at 1,920 x 1,080 with detail set to high, it achieved a smooth 35.5 frames per second - leaving enough headroom for anti-aliasing at lower detail settings. As a whole there's enough performance here to play many modern games at reasonable settings.
Overall, then, the Studio XPS 16 is an interesting machine. Like the 13.3in version there are a few things that could do with tweaking, such as the keyboard, but it's basically a solid and attractive machine. We do wonder, though, whether the majority of people that are more interested in a multimedia machine than photo editing will want to pay more for the Dell's RGB LED display over the similar HP HDX 16.
We can't recommend the Dell Studio XPS 16 to everyone because HP's HDX 16 offers a similar feature set at a keener price. However, if you've been hankering after a notebook with desktop quality colour fidelity, then it makes a tantalising proposition - especially when, in the greater scheme of things, the option isn't even that expensive. As such it gets a (qualified) Recommended Award.