I have an SS51G with the following:
2.26GHz P4 CPU
512MB Corsair Memory
ATI AIW Radeon 8500DV Video Card
Turtle Beach Santa-Cruz Sound Card
2 x Western Digital WD1200JB Hard Drives (No floppy)
Lite-On 16x DVD Player (Black)
Plextor PlexWriter 40/12/40U External USB 2.0 CD-RW
Peripherals (not that this is pertinent):
Dell 1900FP Monitor
Klipsch Promedia 5.1 Speakers
Microsoft Natural Keybord Pro (beige...eeeeeewwwwww)
Microsoft Intellimouse Explorer 3.0
Anyways, I have about as much as you could possibly fit inside one of these, and everything seems to be running fine. I wouldn't worry about it. Nothing against AnandTech, but in the future, you'd probably be better off asking your SS51G questions in the
Small Form Factor & Quiet PCS Forum over at ViaHardware. People who actually work for Shuttle frequent that forum, and you will get quick answers to most any question. There's a much higher concentration of people who know about the Shuttle barebones systems.