Design and build
With a glossy front panel and a classy matte finish on the sides, the X51 is just as pretty standing upright as it is lying down flat.
Attention to detail, with a logo that rotates with its orientation and customisable front and side lights, is impressive – although unlike most PCs you'll need to find space for a chunky external power brick.
Performance and graphics
The mid-range i5 we tested hits the sweet spot between performance and price. It's blazing fast, although graphics leave a bit to be desired compared to super-high-end PCs; even the top-spec GeForce GTX 555 couldn't run Battlefield 3 on Ultra settings. That said, it should play any game you throw at it in detail-rich 1080p - that's sharper than most Xbox and PS3 titles.
The X51 is relatively power-hungry when the going gets tough, but it still uses much less energy than a typical PC. At peak, the Xbox 360 consumes about 90W at full whack whereas the X51 is more around the 165W mark.
While idling or playing movies, the X51 is very quiet – a smidge louder than typical Blu-ray player, but not enough to spoil an intense moment. The fans don't spin up much when running games either, though if they do kick in then the whole neighbourhood will know about it. We look forward to the day when PCs don't sound like aircraft taking off.
Built-in optical audio, Windows Media Center and the ability to stream from the web make the X51 an ideal all-in-one entertainment machine for the lounge. It's a little odd then, that Alienware hasn't bundled wireless peripherals, and there's no Blu-ray player either – that's only available as a £90 option on the top-end model.
Because it's a 'real' PC – not built from laptop parts like the Mac Mini - the X51 is futureproof. Opening it up and swapping out components, including the graphics card, and processor, is easy, which means that in a couple of years it could be outperforming the next generation of dedicated consoles.
Versus Xbox 360 for gaming
Both the Xbox 360 and the PS3 are beginning to struggle with the latest games. The X51 can handle Skyrim with almost all settings at max – it looks miles better and loads much faster too. While the Xbox controller is comfortable and versatile, the level of precise FPS control you get with a keyboard and mouse means going back to the Xbox feels like running underwater.
You'll get a lot of fun out of the Xbox 360, and it's much cheaper than the X51 – but the fully-featured Alienware is where the real gaming power lies these days.
Versus Xbox 360 for media
There are lot of goodies to be found on the 360's dashboard including Netflix, Sky Anytime, Lovefilm and now BBC iPlayer plus it can stream content from your computer. But a PC will allow you access to any online music, movie or catch-up TV service, and can also stream to any other device – plus the X51's 1TB capacity is ample for ripping and storing a library of music and DVDs.
It can't compete with the Xbox 360 on price, but if you're prepared to stump up the cash, the well built, well specced and versatile Alienware X51 is a killer addition to your study or living room.