What free anti-virus do you use?

[xide]

I keep looking for a good free anti-virus to offer my clients, I used to give out MSSE until it quit working with XP (yes I still have a lot of XP clients) I've tried a few and I get complaints that they cause the system to run slow (users with less than 1-2GB of ram) or it starts to nag them about registering or upgrading. Of course I like repeat business so I don't expect anything great, but nothing that is worthless either.

Anyone have and recommendations to try?

These are my only requirements really.
a) runs on a system with less than 1GB of ram
b) no nagging/registering screens

Thank you kindly in advance. Cheers!

[Dustin D]

We are re-sellers of AVG here so we generally put AVG on things. It's pretty non-intrusive, you can schedule scans, and it never really tries to get you to pay except during major updates. Even then I've only had one customer manage to install a trial version of their Internet Security that way. I like it because even though you aren't paying for real time scanning it still scans things as they are downloaded. It's not invincible, but not much is. We put it on any unprotected device that comes in with an owner that refuses a paid version.
Specs from their website:

Minimum system requirements for AVG:
Processor: Intel Pentium 1.5 GHz or faster
Memory: 512 MB of RAM (Windows XP) / 1024 MB of RAM (Windows Vista, Windows 7, Windows 8)
Hard disk free space (for installation):
AVG Anti-Virus Free: 1200 MB

Recommended system requirements for AVG:
Processor: Intel Pentium 1.8 GHz or faster
Memory: 1024 MB of RAM
Hard disk free space (for installation):
AVG Anti-Virus Free: 1500 MB

[piksel]

Well, I also look for some free antivirus...

[xide]

Thanks Dustin I appreciate that! I think I will give it a try .....but it really doesn't offer real time scanning? I was under the assumption most did.

[Dustin D]

I was under the assumption that it was a feature of paid AV solutions and that the free versions mostly offered scheduled scanning. I could be wrong of course.

[Huskylogic]

Consumer Reports rates Avast the highest. I've tried AVG in the past but found that it was a big resource hog when it came to older machines. It's been a few years so they might have changed. I've been using Avast, because they seem to be getting great reviews and ratings. I do have some clients who have the paid versions of AVG, and love them. They all have faster machines though.