Underneath the skin
Now that we've taken a look at the MEGA651's external attributes, let's take a peek inside.

Removing the MEGA's aluminum skin reveals cramped internals that look a lot more disorganized and messy than they really are.

Unlike Shuttle, MSI has gone with a more traditional AGP/PCI slot orientation in the MEGA651. The system's AGP slot is "inside" the PCI slot, just like it is with normal ATX and micro-ATX motherboards. That means one could theoretically squeeze a Dustbuster-sporting GeForce FX 5800 Ultra into the MEGA, but why anyone would want to do that is beyond me. With that much blower power in the system, I fear the tiny MEGA might be prone to liftoff.

With its AGP slot buried deeper inside the system than Shuttle's cubes, installing a graphics card is a little more difficult with the MEGA651 than with an XPC system. By the same token, PCI card installation in the MEGA651 is easier than it is in one of Shuttle's cubes, which have the PCI slot on the inside.

As Shuttle does with its cubes, MSI covers up any internal metal surfaces that could potentially short an installed graphics card. That might not seem like a big deal, but it's a nice little touch that could save users some potentially expensive magic blue smoke.

The MEGA's cramped conditions necessitate a little creativity when it comes to heat sink retention systems. I'll dive into the MEGA's unique cooling system in a moment, but for now, take in the minimalist heat sink retention studs. Normally, I'd be wary of a heat sink mount that offered so little support. However, the Pentium 4's heat spreader should keep the processor core protected through even a clumsy heat sink installation.

Uniquely, the MEGA's two DIMM slots are situated along the edge of the board, opposite the AGP and PCI slots. This placement makes memory installation quick and painless, and it should also keep the DIMMs cool, since they're not mounted directly under the system's hard drive as in an XPC. The MEGA's external skin even has a few venting holes near the DIMM slots to help keep them cool.

Towering over the DIMM slots are the MEGA's drive cages, which can be removed individually. The lowest drive bay is occupied by the system's memory card reader. The other two are available for a hard disk and optical drive, respectively. As I mentioned earlier, the system's card reader is only an option; it can be removed and replaced with a second hard disk or a floppy drive.

Buried under the drive bays are the majority of the MEGA motherboard's chips, including the actively cooled SiS 651 north bridge chip. In such cramped conditions, I have to wonder just how much air flow the north bridge is really getting. Still, the MEGA was stable throughout testing in my steamy, air conditioning-less basement suite.