Dell XPS 15z notebook review

Performance

The XPS 15z's sleek looks might lure consumers in, but it's the system's potent combination of internal components that's likely to trigger a purchase.

Dell's notebook packs a fair amount of punch for £899, and to see just how quick it is we're comparing it to the following seven notebooks:

CPU and GPU performance

The MSI CX640 and Dell XPS 15z both feature an Intel Core i5-2410M processor that's undoubtedly quick. Combined with 4GB of memory, it makes the XPS 15z feel nippy in use and the dual-core, quad-thread CPU has absolutely no trouble running multiple applications at once. Playing multiple videos while browsing the web with over a dozen open tabs showed no signs of slowdown. It's a shame Dell doesn't provide an SSD option, though, as that would move the XPS 15z's responsiveness up from nippy to near-instant.

Cinebench confirms the potency of the Core i5 CPU. It's comfortably quicker than the previous-generation Core i5 chip featured in the HP Envy 14 and will offer plenty of performance for most users.

Here's where the XPS 15z flexes its muscles. Armed with two graphics solutions - an Intel HD 3000 IGP and an NVIDIA GeForce GT 525M GPU - the notebook uses NVIDIA Optimus technology to dynamically switch between the two based on the needs of the user. The switch is seamless and it allows the machine to offer more graphics power from the NVIDIA card when needed, while falling back to the Intel IGP to save power when graphics aren't a priority.

Looking first at GPU oomph, 3DMark06 proves the GeForce GT 525M to be a more-than-capable performer with a score in excess of 8,000 - the highest in our line up. But while the GPU's more than enough for hardware-accelerated video content, its gaming mileage will vary. To give you an idea of the chip's capability, we scored an average frame rate of 27.6 when playing Just Cause 2 with medium quality settings (2xAA, 8xAF) at 1,366x768. That's a 50 per cent boost over the 18.4fps scored by the GeForce GT 520M-powered MSI CX640, but not enough to catch the AMD Llano system. With its IGP and discrete GPU joined at the hip in CrossFire, it scores an impressive 43.4fps.

Games are playable on the XPS 15z, but be prepared to sacrifice quality and note that the powerful discrete GPU does have a few drawbacks. When stressed in Just Cause 2, the GPU fan becomes intrusively loud, and the base of the notebook turns noticeably warm to the touch.

Power consumption and battery life

Power consumption is a little on the high side, though, and that's likely to have an impact on battery life.

In our battery rundown test - which entails looping a 720p movie clip with 50 per cent screen brightness and all wireless radios disabled - the XPS 15z managed to keep going for just under three-and-a-half hours.

That's less than half Dell's quoted battery life, so what gives? Turns out the XPS 15z is choosing to use the NVIDIA GPU while playing back a single 720p trailer. That's something the Intel HD 3000 IGP should be able to handle, so we decided to re-run the test with the NVIDIA GPU disabled, and the results are interesting. With the Intel IGP handling video playback, power consumption drops to 21W and battery life is extended to 287 mins.

Close to five hours of video playback suggests that the capacious 64Whr battery is being to good use, but you'll need to configure when you want the NVIDIA GPU to come to life in order to maximise system longevity.