The way i have always understood is an 1.6 Atom is similar to a Pentium 3 except it acts as if it has dual cores. I think the bigger issue though is that most netbooks that i have seen use an integrated intel chip that uses your systems memory. For example my netbook only has 1gb of RAM and between 40-60% of that is used before any game is run.
The most intensive thing I have ran so far was the original half life but that was back under XP eariler this year and since then even video playback has degraded.
I reckon if it does run you would be limited to very small battles.
My Netbook;
Intel Atom CPU N270 1.60GHz (2 CPUs)
1024MB RAM
Intel GMA 950
Windows 7 (Yes I am insane)