Most notebooks come with a six-cell battery as standard, however for the purposes of this review we were sent both six-cell and nine-cell extended batteries. As previously noted, with the six-cell battery the XPS M1330 weighs just a fraction over 2kg. This is a nice portable weight for a notebook of this size, though it doesn't quite match Sony's SZ in this respect, which comes in at under 1.8kg with the same capacity of battery. In cheaper configurations Dell also allows for a four-cell battery that reduces the weight to 1.79kg, though you'll take a significant hit in the battery life department with this option.
Interestingly the nine-cell battery shares a similar design to that found on the MSI PR210, with a ridge shape that acts as a stand. This actually provides a very nice angle for using the notebook, while the nine-cell only increases the total weight of the notebook to an acceptable 2.15kg. As such, for those who require longer battery life this is quite a compelling option and although you can't specify both six-cell and nine-cell batteries at point of purchase, you could buy them separately.
For battery testing we've run a couple of tests, including a DVD playback test and one based on general real world usage. For the DVD Playback test screen brightness was set to around 70 per cent, which proved to be a nice balance between the brightness required to bring out enough detail, while maintaining decent black levels.
With the six-cell battery this produced a total of two hours and 23 minutes playback, which is a good return and will ensure you can watch most films on a single charge. With the nine-cell this was extended to just under four hours, at three hours and 58 minutes -- more or less double that of the six-cell. Overall these results were very encouraging, proving that you can watch DVDs at acceptable brightness levels and not resort to mains power halfway through a film.
To gauge battery performance under more typical conditions the M1330 was used for word processing and Internet browsing, in this instance using the six-cell battery with display brightness set to its maximum and with Wi-Fi enabled. While conducting our test it was very evident that as well as being great to look at, the M1330 is also a great notebook to use. It runs quietly and coolly during normal use, while the keyboard layout is truly excellent with none of the annoying issues one sometimes finds. Keys themselves are crisp and responsive, making typing a pleasure; while the touchpad below the keyboard is well placed and doesn't obstruct typing.
After two hours and 55 minutes the system ran out of juice, shutting down completely. This is an acceptable result, but its slightly short of the Sony SZ61VN which managed around 25 minutes longer thanks to its ability to use Intel's integrated graphics. Obviously reducing display brightness will improve things slightly, but the cumulative difference in battery life will always remain in favour of the SZ and the gap would likely increase given identical conditions. Of all things, this is one of the few areas the M1330 doesn't match its nearest competition.