Inside the beast
Pulling off a sleek form factor exterior is relatively easy, but making everything work inside the chassis is considerably more difficult. This is where Shuttle's experience really shines, and so it should, since Shuttle has now made a business of building complete systems with its chassis.
A handful of thumbscrews is all that holds the SD39P2's aluminum skin in place, making it relatively easy to get at the guts of the beast. Even with just the outer skin removed, the system's internals are remarkably accessible.
Up top, we find a couple of 3.5" hard drive bays held in place by standard screws. Shuttle's older P-series designs had largely tool-free internals that made liberal use of plastic struts and clips to hold everything in place. It was a pretty slick setup, but one that Shuttle ultimately abandoned in favor of a more traditional—and probably more durable—design. I'm not even sure I prefer one configuration over the other; the older plastic clips made installation a snap, but they certainly didn't hold drives as tightly as the SD39P2's metal cages and screws.
Around the left side of the system, we have relatively easy access to all four of the SD39P2's DIMM slots. Amazingly, there's quite a bit of clearance for taller memory modules. Corsair's XMS Pro DIMMs fit easily, and you can even squeeze the company's taller Dominator modules into the system without removing additional components.
From this angle we can also see that Shuttle has gone with passive chipset cooling for the 975X Express. The P2 chassis has a generous amount of internal airflow, so there's little need to worry about the chipset overheating.
Turning our attention to the other side of the system, we find the SD39P2's PCI and PCI Express expansion slots. Shuttle's first stab at a Core 2-compatible cube featured dual PCIe x16 slots and support for CrossFire multi-GPU configurations, but this latest attempt opts for a more sensible combination of x16 and standard PCI slots. The XPC chassis only has room for two expansion slots, and you're generally better off with a single double-wide graphics card than a pair of single-slot cards in CrossFire. It's nice to have a PCI expansion option, too, if only because sound cards remain wedded, tragically, to the PCI bus.
In case you're wondering, it is possible to squeeze a GeForce 8800 GTS into the SD39P2 with relatively little drama. Shoehorning the larger GTX into the, er, shoebox is a little more complicated, particularly because the system only has one six-pin PCIe power connector; the GTX requires two. Incidentally, the SD39P2's power supply is a 400W unit rated for a peak output of 450W.
Sliding any double-wide graphics card into an XPC can be a little tricky, and it's common for the bottom tips of the PCI back plate to make contact with the motherboard. Shuttle has you covered, though; a plastic cover protects sensitive motherboard components between the expansion slots and PCI backplane.
Getting at the SD39P2's DIMM and expansion slots is relatively easy with just the outer skin removed, but to access the CPU socket and internal drive bays, we have to pop the XPC's top. Out come the hard drive trays, which hold the entire upper drive cage in place, giving us a much better look at the system's LGA775 socket.
