Shuttle had quite a few variants of the XPC throughout the early-to-mid 2000s and later on. Some of these share components, while others look similar but might as well be worlds apart. This should hopefully help break down some of the differences between types. This is not an exhaustive breakdown. There are some oddball one-off types that may get missed.

Before we begin though, we need to decipher the actual model names, as there is a method to Shuttle's madness, here. For example, let's look at the SB61G2.

The first character (S) is just there for show, in this case it likely just stands for “Shuttle”
The second character (B) denotes the chipset. In this case, B stands for Intel. Here's a quick list of known chipset variants:

• A: AMD (late 2000s)
• B: Intel
• N: Nvidia nForce
• K: VIA
• S: SiS
• T: ATI (Only used for two models, it seems)

It should be noted that the original XPC (the SV-line) do not adhere to this (though it could be argued the V stands for VIA in that case, too).

The third and forth characters are the iteration. In earlier models this just incremented with new models but in later models (such as the SA76G2) it also indicated chipset. (In the SA76's case, it used an AMD 760G chipset. In the SH61R4's case, it uses an Intel H61 chipset, so on and so forth.)
The fifth and sixth characters (G2) denote the chassis and front panel. In the case of the SB61G2 we used as an example earlier, this would mean it's using a G chassis with a front panel used across the G2 line.

In a general sense, chassis components from the same series are compatible with eachother with some difficulty. Notably with the G-series, it was such a long-running chassis that small revisions have been made to it over time to accommodate newer CPUs and components. Those differences will be pointed out in their respective sections.

General Notes:

This is Shuttle's mid-00s bread and butter. I'd wager a vast majority of people who had a Shuttle in this time period had one that was in the G series. It also had a vast collection of accessories (like carrying bags!) made for it.

For the most part, the chassis components are cross compatible. The G chassis has mounting provisions for every type of front panel Shuttle used with this series, both screw posts for the G2 faceplates, or snap-in points for the G5 faceplates.

The only gotcha here is that the front panels have exact port cutouts that may cause problems if you attempt to mix and match front panel components. Pay attention to this as you work. Some of the front panel boards also have different means of connecting to the motherboard (some use the standard headers you'd see in a full size PC, some use a smaller pitch connector, and some use a ribbon cable).

However, in every case observed so far, the front panel essentials (that is, the power button, reset button, and LEDs) all use the standard front panel header connector that you'd see on a full desktop, and most (if not all) Shuttle motherboards have a standard header on board just in case. So worst case, you can connect the buttons and LEDs directly to the motherboard and potentially forego the front panel USB/FireWire/audio.

The ribbon cable style also appears to be cross compatible with other boards and front panels that use it. (Observed moving from SS30G2 board to SA76G2 board in the same chassis.)

Notable tweaks and revisions

Due to being Shuttle's long-running chassis for the 2000s, some small tweaks were made later on to accommodate newer CPUs and such. There are two big ones to watch out for:

Rear exhaust/fan mount: On the newer G-series Shuttles, this was expanded to allow a larger fan and heatsink to be installed, ostensibly due to Prescott Pentium 4s (and their tendency to run toasty). The CPU heatsink mounts are otherwise the same, so you could get away with swapping components here if needed, however the bigger heatsink won't properly bolt up to a smaller rear exhaust. (You can probably get away with this in reverse but it'll look weird.)

CPU cooler mount: On the G-series the CPU cooler (Shuttle's “ICE” system) screws into the chassis, also acting as a means of holding down the motherboard. For the early G chassis, the mount points were fairly consistent, being more toward the rear and centered. Late in the 00s, however, Shuttle moved the CPU closer to the front of the case, and offset it to the right (if looking at the system from the front). These still mate up to the rear exhaust all the same (though they use the larger rear fan mentioned previously).

This is a hypothesis but it seems this may have been to allow the older (and potentially outgoing) G series chassis to share some components with the newer and different chassis types. Case in point: The SA76G2's cooler is shared with the SH67H3.

G4 power supply mounts: The G4 variation seems to have a subtle tweak to the power supply mounts and might use a smaller power supply compared to other models in the G-series.

G/G1: Both drives visible from the front, as re the ports. Front bezel is screwed into the chassis, with a transparent acrylic in multiple different colors (clear, blue, green). You could also put designs behind the acrylic in some cases (and Shuttle sold kits for this, as well).

The buttons and LEDs are mounted to the bezel itself, beware of this when removing the bezel completely from the chassis.

G2: By far the most common. Same as G but this time sporting a metal plate instead of a transparent acrylic vanity plate, and said plate is actually inset into the front panel. Power buttons and LEDs are circular, and toward the lower center of the front this time. Further, these are mounted to the XPC's chassis internally, so the faceplate (and vanity plate) can be removed without disturbing the wiring. However, be careful as the buttons and LEDs have surrounds that can fall out and are easily misplaced once the vanity plate is taken off.

G4: A departure from the G/G2, this variant eschews the externally accessible 3.5“ bay and replaces it with a card reader. The power button and LEDs are relocated to the lower left (and I assume this means they're mounted to the front bezel rather than to the chassis itself). The front of the G4 looks to to be a snap-in affair, foregoing the screws used in the G/G2.

This model variation also notably tweaks the G chassis subtly in the rear with a smaller power supply cutout than is seen on the G/G2 models. It is therefore assumed that power supplies are NOT interchangeable with this model and others.

(Note: I have not seen a G4 variant in the wild. Please do email me if you have one and would like to document it!)

G5: Like the G4 variant, this one snaps in and isn't fastened via screws. The buttons and LEDs are once again moved to the center (and mounted to the bezel, not the chassis), but nudged up to just under the 3.5” bay. And yes, this design does bring back the 3.5“ bay that was turned into a card reader with the G4 variant. However, unlike the other Shuttles in the G series, this one moves everything behind flip-down doors for a sleeker appearance.

G5M: This is just the G5 variant with a mirrored finish and an LCD baked in that Shuttle calls the Variable Function Display. This was notably only used in two models (three if you count the Deluxe trim of one of those two models).

NOTE: Page in progress, more added as I can
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