Antivirus lightweight and functional

[Jagwire]

I wonder if you know a virus very light (it is a priority) and functional that would work on the (very) old configs (Pentium III 850 MHz for example ).

For the moment all my computers are avast! but I do not know if this is the top level security (I saw several comparison tests that are quite afraid), I thought to go Antivir. But before making a stupid I wanted to know if it works well
If you have any other AV offer me but do not hesitate to do intensive advertising for your favorite AV SVP

Thank you in advance

[Wingit]

It depends on the OS in this case. :-)
If it's 98, Antivir is not compatible (because, remember, Win 98 is no longer supported by Microsoft).
For the rest, no problem, on the contrary, being lighter Antivir avast.

[opaper]

Currently, 2 Free AntiVirus is the best performing AVIRA Antivir and GRISOFT AVG 8.0.

[Aikonik]

Personally I tried Avast, AVG and AntiVir.
I finally returned to Avast is not too great a colander and it is discreet.

I do not hide that from time to time (every two or three months) I do a scan with the trial version of Kaspersky, the best antivirus for my taste (but paid).

[CapriAnupam]

I have used all the three. I am now using Avast. Its a great antivirus. Keep avast on the PCs.