Behind the black
As with all G-Series systems, accessing the SG33G5's internals involves little more than removing a trio of thumbscrews and sliding off the case's outer skin. That's only the first step in the disassembly process, but it's enough to gain access to some of the guts of the system.
Around the right, we see the XPC's 250W power supply, which can supply a maximum of 16A on its 12V rail. That should be more than enough power for a home theater PC, since you'll want to optimize that kind of system for low power and noise levels. It may not be enough juice to supply the latest crop of high-end graphics cards, but for reasons we'll touch on in a moment, that won't be an issue with the SG33G5.
The PSU's lack of a six-pin PCIe power connector will be a problem if you're planning to run some of even the latest mid-range graphics cards, though. Fortunately, those cards typically come with the necessary adapters in the box, and the XPC's PSU has enough spare four-pin molex connectors to feed them.
Rotating the system 180 degrees reveals why you don't need to worry about powering high-end graphics cards—with the PCIe x16 slot on the outside edge, there isn't enough room for double-wide graphics coolers. It's unfortunate that Shuttle places this arbitrary limitation on the system, particularly because we've used a number of double-wide graphics coolers whose low noise levels make them perfect for home theater PCs. However, there's only so much room inside this XPC's cramped chassis. If you have your heart set on running a double-wide graphics cooler, you can always dremel the chassis' thin aluminum skin.
Just above the PCIe x16 slot, Shuttle has fitted the SG33G5 with a standard PCI expansion slot. PCIe peripherals are still painfully rare in the wild, so going with PCI here ensures compatibility with the wide range of TV tuner, audio, and other expansion cards already on the market.
From this angle we also have a better look at the XPC's pair of DIMM slots running parallel to the front edge of the chassis. The slots look a little cramped from here, but it's surprisingly easy to slide modules into place since you have access to the other side of the case.
To gain greater access to the rest of the SG33G5's internals, all you have to do is remove a couple of screws and pop out the system's internal drive bay cage. This lift-out cage makes installing drives much easier and also opens up the interior of the case so you can get at the CPU socket.
That socket lies beneath the latest incarnation of Shuttle's ICE cooler. Much like ICE designs of old, a trio of heatpipes channels heat away from a copper base to an array of cooling fins that sit next to the chassis' rear exhaust. Four screws secure the cooler to the chassis, sandwiching the motherboard between them for a snug fit. The screws are just the right length, too, so it's impossible to accidentally over-tighten them.
The ICE heatsink works in conjunction with a 92mm fan to push warm air across the radiator fins. This seven-blade unit is also responsible for chassis cooling, and apart from the fan tucked away inside the power supply, it's the only active cooling element in the system. Having a single, extremely quiet fan responsible for CPU and chassis cooling keeps the SG33G5's noise levels nice and low. However, keep in mind that if that fan fails, the entire system is likely to overheat quickly.
Note that the fan uses a four-pin connector, allowing it to ramp fan speeds smoothly rather than stepping between predetermined high and low speed settings. Few things are more annoying than a system wheezing back and forth between fan speed settings like Britney Spears bounces in and out of rehab. Actually, Britney Spears is more annoying.
Turning the fan on its face reveals another little touch that's worth noting: Shuttle uses rubber grommets to dampen each point where the fan shroud makes contact with the case. This should help to reduce fan-induced vibrations, lowering noise levels in the process. Shuttle could run with this theme a little more, including similar grommets to isolate the drive cage from vibrations induced by optical drives and hard disks.
With the drive cage, heatsink, and fan removed, it doesn't take much work to pop out the SG33G5's motherboard for a closer look. There isn't much to see on a motherboard this small, of course, but the G33 Express chipset impressively requires only passive cooling within the cramped confines of the XPC chassis. Here we can also see that Shuttle is using "solid state" capacitors throughout the board. These caps should be less prone to bursting than conventional designs.
If you're planning on running a discrete graphics card in lieu of the SG33G5's integrated graphics, you'll need to flip a row of jumpers just above the PCIe x16 slot. This chore isn't terribly inconvenient, but we haven't had to fiddle with onboard jumpers in a long, long time. These days, just about everything can be done through the BIOS, and since all of Shuttle's previous XPCs have been smart enough to disable their IGPs when discrete graphics cards are installed, we expected the SG33G5 to do the same.
