Size doesn't really matter... at least not when it comes to CPUs. Via Nano (formerly known as Isaiah) isn't shy when it comes to running the latest and more demading 3D games, in this case: Crysis itself..
The Mini-ITX 2.0 platform consists in a high-performance (and efficient) CPU like VIA's Nano, DirectX 10 support for 3D and Blu-Ray playback, 6-channel audios, and a PCI Express x16 slot for high-performance graphics.
In a high-end system, with a 1.8Ghz Nano, CN896 chipset, and an nVidia GeForce 8600 even games like Crysis can be run (as seen on the video.)
If this isn't enough to show that the Nano seriously is an alternative to Intel's Atom, I don't know what will.