Man of Honour
Have you used ones like BitDefender? That is the definition of unobtrusive.
Not that RAM usage matters these days but BitDefender uses about 18MB of RAM, what's Panda like? Personally not seen any issue with gaming myself.
I think Panda cloud has Bitdefender Free beat on small footprint,as to AVG and Avast they have been fine in my testing on Win8.1 over the last few months or so.
I currently use Panda Cloud and Avast on my two 8.1 PCs.
Bitdefender Free version I avoid due to gaming issues (ME3 crashing etc)when you try to run games like ME3 via Origin launcher.
Bitdefender Free lasted about three hours on my PC before I had to remove it.
I also use Malwarebytes Free version for manual backup scans now and then.
I don't know why anybody would not use an AV with Windows,there are plenty that are free,small footprint etc and no popups,its just another layer of added security which can't be a bad thing.
Linux I can understand since I don't use an AV on my Linux distros.
Not that RAM usage matters these days but BitDefender uses about 18MB of RAM, what's Panda like? Personally not seen any issue with gaming myself.