Need Firewall Suggestions (with questions)

I need a firewall that has a small footprint for both my older P3 rig and my new S939 build. ZoneAlarmPro is such a memory demanding software that as soon as the subscription expires on my P3 it will be uninstalled. It freezes and slows down my PC to the point of frustration in almost every capacity you can imagine. But one thing ZAPro 6 has provided is tremendous stealth security. I just tested it yesterday and all ports were secure. So, what to replace it with that isn't so resource demanding? I am looking for something highly dependable that protects both incoming and out-going information and it MUST supply stealth.


I still search for answers to many of my questions, one of which is: Does a software firewall need to be upgradable or are firewalls basically as is and thus there really is no need to to upgrade? I really hope someone here can answer this for me.


Many still like the free download of Sygate 5.6 even though Sygate is no longer in business. And here comes another of my questions: Would you load a 2 year old firewall on a new system or is this a moot point?


AVG seems to have a good anti-virus but their firewall is not highly respected. There is Kerioo (sp?) 4.0 Professional (Sunbelt Software) that seems good and Kapersky is considered one of the very best anti-virus protectors along with BitDefender. Kapersky's firewall, however, does not get good marks.


If you know of a good one that you trust for your high-end PC's and has a small footprint please let me know. (sorry about the spelling of the names; I'm sure I butchered at least 2!)