Just for the record US$400 gets you this:
1. AMD Phenom II X4 Processor 955 (3.2GHz) AM3, Retail, with Heatsink and Fan
2. Asus M4A78-EM Socket AM2+/ AMD 780G/ HDMI/ A&V&GbE/ MATX Motherboard, Retail
3. Kingston KVR800D2N5/2G D2-800 4GB Memory (2 x 2GB) Or KVR800D2K2/4GR Kit (2 x 2GB)
Yet it would still be crap, when you have MOS/OS 4 flying in much less demanding hardware.
I would never buy such a low system for once, it would be a complete waste of space, where a mac mini or this presents themselves much more tempting.