The performance numbers that we did get are nice and high, as you'd expect for a machine such as this. The problem is though that they're just not high enough, especially at the price that Dell is asking for this machine.
The 3DMark05 score at 1,024 x 768 is 9,092 but the first system we tested with 7800 GTX SLI (on its launch date), the Evesham Axis 64 Decimator 78, obtained 11,023. Moving to Far Cry at 1,600 x 1,200 with FSAA and AF enabled, the Dell gets 81.03fps, while the Evesham got 90fps. Looking at the Dell's Half-Life 2 scores, the are essentially the same from 1,024 x 768 all the way up to 2,048 x 1,536, a clear indication that the machine is CPU limited. The Evesham was also CPU limited in Hlaf-Life 2, but it's Athlon X2 4800+ pushed this to 115fps.
The next problem is that the Evesham machine was much cheaper than this Dell. Of course, it wasn’t as fully featured, and when I priced up an Evesham machine of similar specification is was actually even more expensive than the Dell. However, that was based on an Athlon X2 4800+, so you know that you'll be getting better performance.
Essentially, Dells slavishness to Intel seriously hampers the appeal of the XPS desktop as a serious hardcore gaming machine. Sure, it's fast but you know that an Athlon system of the same price, whether it's a dual-core X2 or a FX-57 will give you better gaming performance.
If you're aware of this, or you're just an Intel fan boy and don't care that you could get even more performance elsewhere, then there's a lot to love about the Dell.
The Dell XPS is generally very impressive and while it's very expensive you do get a great specification for your money. It's also great to look at, it's very well built and it's not too loud. However, it's Intel based, and when it comes to games, AMD is faster. A great machine then, but it's not the final word in gaming desktops.