WE'VE WRITTEN quite a few reviews of Shuttle's cube PCs by now, yet I still can't help but marvel over these little boxes every time a new one comes along. Shuttle is obviously committed to improving its XPC line and expanding its appeal. Since the first SV24 cube appeared, Shuttle's cubes have gotten much faster, vastly quieter, arguably better looking, and—praise be!—have gained an AGP slot. Shuttle has also expanded its XPC line with versions for Pentium 4 and Athlon processors, riser cards for additional audio and video outputs, and a range of color-coordinated accessories, including a cube tote bag.

At some point, it occurred to me: these guys are bent on building a mini-PC empire.

Actually, that point was probably Computex this past year, when the Shuttle rep said to me: "We are bent on building a mini-PC empire" as he slammed his fist on a desk, scattering Shuttle trade-show schwag everywhere. Or something like that.

Anyhow, the latest building block in that empire is the fastest XPC we've seen yet, and it benefits from all the improvements Shuttle has brought to the XPC line. The SB51G is based in Intel's 845GE chipset, which is one of the fastest chipsets available for the Pentium 4, as we found in our recent review. The 845GE gives this new cube support for DDR333 memory and for Intel's soon-to-be-unleashed Hyper-Threading technology. Imagine cramming a pair of virtual CPUs into a PC the size of a toaster, and you're beginning to understand this thing's jaw-dropping potential.

So the question is: is this new XPC ready to challenge the Standard Beige Mini-Tower Case for supremacy in the enthusiast's heart? We stuffed a Radeon 9700, a half gig of Corsair memory, and a Pentium 4 2.8GHz in this box to see how it moved us. Keep reading to see what transpired.

The specs
The SB51G is based on Shuttle's FB51 motherboard. Remarkably, the microATX-sized FB51 packs in nearly all of the features of a full-fledged PC, plus it has a pair of expansion slots for added functionality. Here's the full rundown of specs:

Notice that the FB51 doesn't support some of the fancier new features out there, like AGP 8X or ATA/133 disk transfer modes. That's because its Intel 845GE chipset doesn't support these features. Honestly, though, don't expect to miss them. These newer standards promise more speed, but that speed is largely unused with current hardware and applications. You'll also notice that the SB51G has USB 2.0 courtesy of the 845GE chipset, and that particular brand of speed will more likely be useful in the near future.

Intel's I/O controller hub chip provides communications and connectivity

Realtek's teesny weensy ACL650 audio chip

Shuttle didn't use the 845GE's "south bridge" I/O chip for everything, though. I suppose doing so would have unnecessarily lowered the number of chips needed on the motherboard, making this thing way too easy to design. Instead, Shuttle used Realtek's inexpensive and popular Ethernet and audio controller chips for networking and sound. Realtek's 8100B provides passable 10/100 Ethernet capability, and the ACL650 pumps out sound on par with that hoary standard, the SoundBlaster Live!. I spent some time listening to the SB51G's audio on a decent pair of speakers, and it sounded no worse than most other PC audio solutions.

Beyond that, the SB51G's specs are mostly self-explanatory. Many of those features manifest themselves as ports at the rear of the PC, like so:

The rear of the SB51G has more ports than the New Jersey shoreline