Hello,
currently searching for good window free firewall and find comodo list at top firewall comparison to others by matousec.com

anyone using it please tell me.

1) It take large memory or not?
2) slowing surfing or online games?
3) Crash or hanged?

Thanks for your advice.

ive try it b4 but not make me impressed

give a try at fRee Sunbelt Kerio FW, its better IMO

plz state the reason why u unimpress.
As for me, having using this firewall for about a month.. i would certainly give it a 5 star rating . After trying the buggy zone alarm.. not so efficient KIS, very hard to use sunbelt, laggy Norton.. i would say that this is the best firewall after the legendary sygate which have been bought by norton.
It was very user friendly.. not buggy.. not too many question asked.. auto update database.. and free!